Published on in Vol 24, No 1 (2022): January

Preprints (earlier versions) of this paper are available at https://preprints.jmir.org/preprint/30026, first published .
Engagement Strategies to Improve Adherence and Retention in Web-Based Mindfulness Programs: Systematic Review

Engagement Strategies to Improve Adherence and Retention in Web-Based Mindfulness Programs: Systematic Review

Engagement Strategies to Improve Adherence and Retention in Web-Based Mindfulness Programs: Systematic Review

Review

1Centre for Quality and Patient Safety Research in the Institute for Health Transformation, Deakin University, Geelong, Australia

2School of Nursing and Midwifery, Deakin University, Geelong, Australia

3Centre for Quality and Patient Safety Research - Eastern Health Partnership, Deakin University, Melbourne, Australia

4School of Psychology, Faculty of Health, Deakin University, Geelong, Australia

5Faculty of Health, Deakin University, Geelong, Australia

Corresponding Author:

Natalie Winter, PhD

Centre for Quality and Patient Safety Research in the Institute for Health Transformation

Deakin University

1 Gheringhap Street

Geelong, 3220

Australia

Phone: 61 3 5227 1100

Email: n.heynsbergh@deakin.edu.au


Background: Web-based mindfulness programs may be beneficial in improving the well-being outcomes of those living with chronic illnesses. Adherence to programs is a key indicator in improving outcomes; however, with the digitization of programs, it is necessary to enhance engagement and encourage people to return to digital health platforms. More information is needed on how engagement strategies have been used in web-based mindfulness programs to encourage adherence.

Objective: The aim of this study is to develop a list of engagement strategies for web-based mindfulness programs and evaluate the impact of engagement strategies on adherence.

Methods: A narrative systematic review was conducted across the MEDLINE Complete, CINAHL Complete, APA PsycINFO, and Embase databases and followed the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) guidelines. Articles were screened using the population, intervention, comparator, and outcome framework. Adults aged >18 years with chronic health conditions were included in the study. Mindfulness interventions, including those in combination with mindfulness-based cognitive therapy, delivered on the web through the internet or smartphone technology were included. Interventions lasted at least 2 weeks. Studies with a randomized controlled trial design or a pilot randomized controlled trial design were included. Engagement strategies, including web-based program features and facilitator-led strategies, adherence, and retention, were included.

Results: A total of 1265 articles were screened, of which 19 were relevant and were included in the review. On average, 70.98% (2258/3181) of the study participants were women with a mean age of 46 (SD 13) years. Most commonly, mindfulness programs were delivered to people living with mental health conditions (8/19, 42%). Of the 19 studies, 8 (42%) used only program features to encourage adherence, 5 (26%) used facilitator-led strategies, and 6 (32%) used a combination of the two. Encouraging program adherence was the most common engagement strategy used, which was used in 77% (10/13) of the facilitator-led studies and 57% (8/14) of the program feature studies. Nearly two-thirds (63%) of the studies provided a definition of adherence, which varied between 50% and 100% completion across studies. The overall mean participant compliance to the mindfulness programs was 56% (SD 15%). Most studies (10/19, 53%) had a long-term follow-up, with the most common follow-up period being 12 weeks after intervention (3/10, 30%). After the intervention, the mean retention was 78% (SD 15%).

Conclusions: Engagement strategies in web-based mindfulness programs comprise reminders to use the program. Other features may be suitable for encouraging adherence to interventions, and a facilitator-led component may result in higher retention. There is variance in the way adherence is measured, and intervention lengths and follow-up periods are inconsistent. More thorough reporting and a standardized framework for measuring adherence are needed to more accurately assess adherence and engagement strategies.

J Med Internet Res 2022;24(1):e30026

doi:10.2196/30026

Keywords



Background

Mindfulness is the act of bringing awareness to the present moment in a nonjudgmental and accepting way [Kabat-Zinn J. Full Catastrophe Living; Using the Wisdom of Your Body and Mind to Face Stress, Pain and Illness. London, UK: Piatkus; 1996:59-66.1]. Mindfulness programs are increasing in popularity as nonpharmacological alternatives to manage both physiological and psychological outcomes related to health conditions [Niazi AK, Niazi SK. Mindfulness-based stress reduction: a non-pharmacological approach for chronic illnesses. N Am J Med Sci 2011 Jan;3(1):20-23 [FREE Full text] [CrossRef] [Medline]2]. Psychological benefits are evident in individuals across a variety of conditions, including cancer [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3] and mental illness [Potes A, Souza G, Nikolitch K, Penheiro R, Moussa Y, Jarvis E, et al. Mindfulness in severe and persistent mental illness: a systematic review. Int J Psychiatry Clin Pract 2018 Nov 07;22(4):253-261. [CrossRef] [Medline]4], and physical health outcomes have been observed through improved blood pressure control [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5] and improved glycemic control in people living with diabetes [Rosenzweig S, Reibel DK, Greeson JM, Edman JS, Jasser SA, McMearty KD, et al. Mindfulness-based stress reduction is associated with improved glycemic control in type 2 diabetes mellitus: a pilot study. Altern Ther Health Med 2007;13(5):36-38. [Medline]6].

Evidence shows that mindfulness skills can be improved through greater engagement with meditation, home practice, face-to-face contact with a facilitator, and a higher number of sessions per week [Strohmaier S. The relationship between doses of mindfulness-based programs and depression, anxiety, stress, and mindfulness: a dose-response meta-regression of randomized controlled trials. Mindfulness 2020 Mar 02;11(6):1315-1335 [FREE Full text] [CrossRef]7]. High adherence to both face-to-face and web-based mindfulness programs results in significant improvements in well-being outcome measures [Ribeiro L, Atchley RM, Oken BS. Adherence to practice of mindfulness in novice meditators: practices chosen, amount of time practiced, and long-term effects following a mindfulness-based intervention. Mindfulness (N Y) 2018 Apr;9(2):401-411 [FREE Full text] [CrossRef] [Medline]8,Spijkerman M, Pots W, Bohlmeijer E. Effectiveness of online mindfulness-based interventions in improving mental health: a review and meta-analysis of randomised controlled trials. Clin Psychol Rev 2016 Apr;45:102-114 [FREE Full text] [CrossRef] [Medline]9].

Mindfulness programs are increasingly being adapted to web-based platforms, providing opportunities for more people to participate compared with conventional face-to-face sessions [Mrazek AJ, Mrazek MD, Cherolini CM, Cloughesy JN, Cynman DJ, Gougis LJ, et al. The future of mindfulness training is digital, and the future is now. Curr Opin Psychol 2019 Aug;28:81-86. [CrossRef] [Medline]10]. Typically, adherence to web-based interventions is low, both with program adherence and study attrition [Eysenbach G. The law of attrition. J Med Internet Res 2005;7(1):e11 [FREE Full text] [CrossRef] [Medline]11]. Program adherence is poorly defined but needs to be standardized across studies; however, it is commonly conceptualized by the number of log-ins or number of sessions or modules completed in a program [Sieverink F, Kelders SM, van Gemert-Pijnen JE. Clarifying the concept of adherence to eHealth technology: systematic review on when usage becomes adherence. J Med Internet Res 2017 Dec 06;19(12):e402 [FREE Full text] [CrossRef] [Medline]12].

Adherence to web-based programs in previous reports has varied between 39.5% and 92% [Spijkerman M, Pots W, Bohlmeijer E. Effectiveness of online mindfulness-based interventions in improving mental health: a review and meta-analysis of randomised controlled trials. Clin Psychol Rev 2016 Apr;45:102-114 [FREE Full text] [CrossRef] [Medline]9] compared with adherence to face-to-face settings, where the rates ranged between 26% and 100% [Stanic J, Barth J, Danon N, Bondolfi G, Jermann F, Eicher M. Adherence to standardized 8-week mindfulness-based interventions among women with breast or gynecological cancer: a scoping review. J Psychosos Oncol Res Pract 2021;3(2):e048. [CrossRef]13] (based on definitions of 100% program completion). Mindfulness programs are often 8 weeks long in duration [Spijkerman M, Pots W, Bohlmeijer E. Effectiveness of online mindfulness-based interventions in improving mental health: a review and meta-analysis of randomised controlled trials. Clin Psychol Rev 2016 Apr;45:102-114 [FREE Full text] [CrossRef] [Medline]9], with higher adherence having an impact on improved participant outcomes [Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14]. There is a need to explore whether engagement strategies can improve adherence to unmoderated web-based interventions. High attrition in telehealth interventions is common and can undermine the potential impact of programs [Linardon J, Fuller-Tyszkiewicz M. Attrition and adherence in smartphone-delivered interventions for mental health problems: a systematic and meta-analytic review. J Consult Clin Psychol 2020 Jan;88(1):1-13. [CrossRef] [Medline]15]. Adherence to mindfulness-based interventions is often poorly defined and inconsistent across studies [Russell L, Ugalde A, Milne D, Austin D, Livingston PM. Digital characteristics and dissemination indicators to optimize delivery of internet-supported mindfulness-based interventions for people with a chronic condition: systematic review. JMIR Ment Health 2018 Aug 21;5(3):e53 [FREE Full text] [CrossRef] [Medline]16]. Promoting long-term adherence and engagement with web-based interventions may maximize the potential outcomes [Beintner I, Vollert B, Zarski A, Bolinski F, Musiat P, Görlich D, et al. Adherence reporting in randomized controlled trials examining manualized multisession online interventions: systematic review of practices and proposal for reporting standards. J Med Internet Res 2019 Aug 15;21(8):e14181 [FREE Full text] [CrossRef] [Medline]17].

Engagement refers to the frequency and duration of use of the interventions, such as logging in and out of programs [Kelders SM, Kok RN, Ossebaard HC, Van Gemert-Pijnen JE. Persuasive system design does matter: a systematic review of adherence to web-based interventions. J Med Internet Res 2012;14(6):e152 [FREE Full text] [CrossRef] [Medline]18]. Strategies to support engagement are used to encourage and draw people back to the interventions [Kelders SM, Kok RN, Ossebaard HC, Van Gemert-Pijnen JE. Persuasive system design does matter: a systematic review of adherence to web-based interventions. J Med Internet Res 2012;14(6):e152 [FREE Full text] [CrossRef] [Medline]18]. Engagement can be enhanced by the design and features of web-based interventions, including the use of gamification, breaking content into manageable blocks, and using a variety of formats to deliver content such as video and visuals [Ubhi HK, Michie S, Kotz D, van Schayck OC, Selladurai A, West R. Characterising smoking cessation smartphone applications in terms of behaviour change techniques, engagement and ease-of-use features. Transl Behav Med 2016 Sep 23;6(3):410-417 [FREE Full text] [CrossRef] [Medline]19]. Other considerations for improving engagement include guided interaction from trained personnel [Kelders SM, Kok RN, Ossebaard HC, Van Gemert-Pijnen JE. Persuasive system design does matter: a systematic review of adherence to web-based interventions. J Med Internet Res 2012;14(6):e152 [FREE Full text] [CrossRef] [Medline]18], asynchronous emails [Arnold C, Villagonzalo K, Meyer D, Farhall J, Foley F, Kyrios M, et al. Predicting engagement with an online psychosocial intervention for psychosis: exploring individual- and intervention-level predictors. Internet Interv 2019 Dec;18:100266 [FREE Full text] [CrossRef] [Medline]20], or web-based features such as reminders [Kelders SM, Kok RN, Ossebaard HC, Van Gemert-Pijnen JE. Persuasive system design does matter: a systematic review of adherence to web-based interventions. J Med Internet Res 2012;14(6):e152 [FREE Full text] [CrossRef] [Medline]18]. Behavior change techniques are engagement strategies incorporated into interventions to promote sustainable changes in behavior [Abraham C, Michie S. A taxonomy of behavior change techniques used in interventions. Health Psychol 2008 May;27(3):379-387. [CrossRef] [Medline]21]. Behavior change techniques, such as notifications and semiautomated tracking, have previously been adopted in app-based interventions and have shown a positive impact on improving engagement [Bardus M, van Beurden SB, Smith JR, Abraham C. A review and content analysis of engagement, functionality, aesthetics, information quality, and change techniques in the most popular commercial apps for weight management. Int J Behav Nutr Phys Act 2016;13(1):35 [FREE Full text] [CrossRef] [Medline]22]. In mindfulness programs, engagement involves regular meditation and daily awareness exercises coupled with intention motivation and commitment to practice [Banerjee M, Cavanagh K, Strauss C. Barriers to mindfulness: a path analytic model exploring the role of rumination and worry in predicting psychological and physical engagement in an online mindfulness-based intervention. Mindfulness (N Y) 2018 Nov 6;9(3):980-992 [FREE Full text] [CrossRef] [Medline]23]. Techniques such as self-reflection are incorporated into mindfulness programs and have been shown to positively impact symptoms in people with anxiety and stress [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24]. More recent techniques such as machine learning [Chien I, Enrique A, Palacios J, Regan T, Keegan D, Carter D, et al. A machine learning approach to understanding patterns of engagement with internet-delivered mental health interventions. JAMA Netw Open 2020 Jul 01;3(7):e2010791 [FREE Full text] [CrossRef] [Medline]25] may also be used to tailor interventions to user-specific needs, thereby maximizing the clinical outcomes of users.

The influence of engagement strategies on program adherence has not been compared across studies; however, it is an important consideration when designing and implementing web-based interventions. In this review, we explored the engagement strategies applied in web-based mindfulness programs and evaluated whether these strategies had an impact on program adherence and retention.

Research Question

The following research question was used in the study: how can engagement strategies be incorporated into web-based mindfulness programs to improve adherence and retention?

Objectives

The objectives of this study are (1) to develop a list of engagement strategies for web-based mindfulness programs and (2) to evaluate the impact of engagement strategies on adherence.


Search Process

This systematic review was guided by the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) framework [Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. J Clin Epidemiol 2009 Oct;62(10):1006-1012. [CrossRef] [Medline]26]. The following databases were searched for terms related to mindfulness, web-based programs, and engagement strategies: MEDLINE Complete, CINAHL Complete, APA PsycINFO, and Embase. The literature search focused on identifying papers published between January 2015 and March 2020. A 5-year period was chosen to capture the most recent web-based interventions. See Table S1 in

Multimedia Appendix 1

Study demographics, examples of search strategy, and adherence, retention, and engagement strategies and outcomes.

DOCX File , 53 KBMultimedia Appendix 1 for an example of the search strategy applied to the MEDLINE database. The reference lists of relevant articles and systematic reviews were searched for additional articles.

Eligibility Criteria

To guide the eligibility and screening process, the PICO (population, intervention, comparator, and outcome) framework [Schardt C, Adams MB, Owens T, Keitz S, Fontelo P. Utilization of the PICO framework to improve searching PubMed for clinical questions. BMC Med Inform Decis Mak 2007 Jun 15;7(1):16 [FREE Full text] [CrossRef] [Medline]27] was used:

Population

Adults aged ≥18 years with a diagnosed chronic health condition or self-reported anxiety or depression were included in the study.

Intervention

Mindfulness interventions delivered on the web through the internet or smartphone technology were included. Mindfulness programs were defined as those focusing specifically on mindfulness-based practice, including programs using a combination of mindfulness and cognitive behavioral therapy (mindfulness-based cognitive therapy).

To allow for engagement strategies and adherence to be analyzed, the interventions had to be at least 2 weeks in duration. There is limited research to describe how long interventions should be to warrant the inclusion of engagement strategies. Previously, engagement was measured by reflecting on the previous 2 weeks [Banerjee M, Cavanagh K, Strauss C. Barriers to mindfulness: a path analytic model exploring the role of rumination and worry in predicting psychological and physical engagement in an online mindfulness-based intervention. Mindfulness (N Y) 2018 Nov 6;9(3):980-992 [FREE Full text] [CrossRef] [Medline]23]. Therefore, we determined that interventions had to be at least two weeks in duration to be included in the review.

Comparator and Context

Studies were required to have a comparison group with a randomized controlled trial (RCT) or a pilot RCT design.

Mindfulness programs developed by research groups for specific populations or commercially available mindfulness programs were tested in controlled trial settings.

Outcomes

Program adherence, study retention rate (%), and strategies such as web-based program features and facilitator-led features were included.

Screening

Retrieved articles were uploaded and managed by Endnote X9 (Clarivate Analytics). Duplicates were removed, and titles and abstracts were screened by 1 author (NH). Full-text articles were uploaded to Covidence to allow cross-checking between authors [Covidence. Veritas Health Innovation Ltd, Australia.   URL: https://www.covidence.org/ [accessed 2020-07-08] 28]. Full texts were reviewed independently by 2 authors, and any disagreements were resolved through discussion.

Data Extraction

A data extraction tool was developed in Microsoft Excel to standardize the extraction. Data were extracted by 1 author (NH), and 10% were cross-checked by the second author (PL).

Study Characteristics

Study data including author, year of publication, country, design, number of participants, intervention type, intervention duration, follow-up measurements, prior mindfulness experience, recruitment method, financial compensation, commercial app name, primary outcome, and primary findings were extracted.

Participant Characteristics

Gender, age, race, ethnicity, type of chronic illness or condition, and patient and caregiver status were extracted.

Adherence

Studies were included in the review when they reported per-protocol and intention-to-treat analyses. Because of variance in reporting the intervention, adherence was assessed in 3 different ways depending on the data available:

  1. As a percentage of compliance with the intervention protocol. For example, some authors defined adherence as 80% program completion, and in this review, we recorded the percentage of the sample that was adherent with 80% program completion.
  2. In groups defined by the study authors. For example, in an 8-week program, some authors reported the percentage of people who were adherent with 0- 3 sessions, 4- 6 sessions, and 7-8 sessions. In this review, we recorded the percentage of the sample that was adherent with the highest group of completion, for example, 7-8 sessions.
  3. Summarized findings of the frequency and duration of use.
Retention

Retention rates were reported for the intervention group at postintervention measurements and subsequent follow-up points.

Engagement Strategies

Engagement strategies were categorized into following 3 groups:

  1. Program features, including chat rooms, discussion boards, diaries and reflective processes, automated reminders, social support, goal setting, mood tracking, customization of content, demonstrations of meditation practice, and immediate feedback on meditation practice;
  2. Facilitator-led strategies, including reminders from the research team to continue practice, contact with the research team to discuss practice or monitoring, and response to well-being scores throughout the intervention; and
  3. A combination of program features and facilitator-led strategies.

Data Analysis

Study characteristics, participant characteristics, adherence, and retention rates were analyzed using descriptive statistics.

Data analysis consists of the following:

  1. Exploring adherence: how adherence was defined, the impact of adherence on outcomes, impact of financial compensation on adherence, and impact of intervention length on adherence.
  2. Describing retention at postintervention measurements and the last data collection point.
  3. Describing engagement strategies (program features, facilitator-led strategies, or a combination): engagement strategies were categorized and summarized using frequency statistics.
  4. Assessing the impact of engagement strategies on adherence: the relationship between engagement strategies and adherence was analyzed by comparing the type of engagement strategy (program features, facilitator-led strategies, or a combination) with the percentage of people who reached program adherence or the percentage of people who adhered with the highest group of sessions (eg, those who completed 7-8 sessions in an 8-week program, as defined by the study authors).
  • Assessing the impact of engagement strategies on retention: the relationship between engagement strategies and retention was measured by comparing the type of engagement strategy with the intervention length, retention at the postintervention measurement and retention at the last follow-up points.

Study Characteristics

A total of 1922 articles were retrieved from the databases and reference lists. After removing duplicates, a total of 1265 articles were screened by title and abstract. Full texts were retrieved for 126 articles, of which 19 were included in the review (Figure 1). Most studies were conducted in the United States (9/19, 47%) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35], were RCTs (16/19, 84%) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31-Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35-Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43], web-based (11/19, 58%) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33-Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37-Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43], and focused specifically on mindfulness or meditation (15/19, 79%) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34-Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39-Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43] (Table S2 in

Multimedia Appendix 1

Study demographics, examples of search strategy, and adherence, retention, and engagement strategies and outcomes.

DOCX File , 53 KBMultimedia Appendix 1) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Schardt C, Adams MB, Owens T, Keitz S, Fontelo P. Utilization of the PICO framework to improve searching PubMed for clinical questions. BMC Med Inform Decis Mak 2007 Jun 15;7(1):16 [FREE Full text] [CrossRef] [Medline]27,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43]. More studies (10/19, 52%) excluded people with previous or recent mindfulness experiences [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43] than those who allowed participants with prior mindfulness experience (6/19, 31%) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41]. Over half of the studies used a combination of web-based and face-to-face recruitment strategies (10/19, 52%) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]. Commercially available mindfulness apps, including Headspace (n=3) [Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36], Calm (n=1) [Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29], and Pacifica (n=1), were used by 5 (26%) studies [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24]. A total of 3 (16%) studies provided monetary compensation for participation [Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33], and 3 (16%) provided access to paid mindfulness apps [Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36]. Intervention duration ranged from 2 weeks to 12 months, with over half (10/19, 53%) of the studies having an intervention duration of 8 weeks [Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43].

Figure 1. PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-Analysis) diagram of the search process.
View this figure

A total of 8 (47%) studies focused on psychological measures as their primary outcome [Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31-Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37-Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42], and 3 (16%) used a physiological measure [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41]. A total of 7 (37%) studies did not report the primary outcome [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43]. Secondary outcomes were predominately psychological measures and program evaluations (8/19, 42%) [Russell L, Ugalde A, Milne D, Austin D, Livingston PM. Digital characteristics and dissemination indicators to optimize delivery of internet-supported mindfulness-based interventions for people with a chronic condition: systematic review. JMIR Ment Health 2018 Aug 21;5(3):e53 [FREE Full text] [CrossRef] [Medline]16,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]. Most (17/19, 90%) studies showed that mindfulness resulted in a significant improvement in outcomes either psychological or physical [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39-Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43] (Table S3 in

Multimedia Appendix 1

Study demographics, examples of search strategy, and adherence, retention, and engagement strategies and outcomes.

DOCX File , 53 KBMultimedia Appendix 1) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Schardt C, Adams MB, Owens T, Keitz S, Fontelo P. Utilization of the PICO framework to improve searching PubMed for clinical questions. BMC Med Inform Decis Mak 2007 Jun 15;7(1):16 [FREE Full text] [CrossRef] [Medline]27,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43].

Participant Characteristics

A total of 34,601 participants were included in the trials. The mean sample size was 165 (SD 134; range 21-500). On average, 71% of the participants were women (SD 18; range 46-100) and 46 years old (SD 13; range 21-76). A total of 8 (42%) studies reported the ethnicity of the participants [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39], and 4 (26%) reported race [Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31-Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33]. On average, White people comprised 74% (SD 14%) of the sample and 90% (SD 10%) were non-Hispanic. Mindfulness programs were delivered to people with a variety of chronic illnesses, with the most common conditions related to mental health (8/19, 42%) [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33-Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38] and cancer (4/19, 21%) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37]. Most (17/21, 81%) studies were delivered to people living with the illness [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31-Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43].

Engagement Strategies

A total of 8 (42%) studies used only program features to encourage adherence, 5 (26%) used only facilitator-led strategies, and 6 (32%) used a combination of the two (Table 1).

Within the facilitator-led strategies (n=13) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33-Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43], encouraging adherence was most commonly done using contact and reminders from facilitators to use the program (10/13, 77%) [Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33-Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]. Contact with a facilitator for discussion of content or well-being scores was used to a lesser extent (4/13, 31%) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43]. In 7 (37%) studies, engagement with facilitators occurred weekly [Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34-Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43].

Table 1. Types of engagement strategies used across studies and their adherence rates.
StudyProgram engagementFacilitator engagementAdherence with study protocol (%)
Chandler et al [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5]39
Compen et al [Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37]79
Kladnitski et al [Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38]66
Kubo et al [Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30]56
Stjernsward and Hansson [Schardt C, Adams MB, Owens T, Keitz S, Fontelo P. Utilization of the PICO framework to improve searching PubMed for clinical questions. BMC Med Inform Decis Mak 2007 Jun 15;7(1):16 [FREE Full text] [CrossRef] [Medline]27]57
Thompson et al [Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33]NRa
Gotink et al [Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14]N/Ab50
Hearn and Finlay [Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39]N/A72
Henriksson et al [Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40]N/A58
Huberty et al [Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29]N/ANR
Moberg et al [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24]N/ANR
Rosen et al [Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32]N/ANR
Russell et al [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3]N/ANR
Younge et al [Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41]N/A53
Bostock et al [Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36]N/A27
Lindsay et al [Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31]N/ANR
Tavallaei et al [Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43]N/ANR
Wahbeh et al [Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35]N/ANR
Wahbeh [Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34]N/ANR

aNR: not recorded.

bN/A: not applicable.

Within program feature strategies (n=14) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37-Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42], participants in 57% (8/14) studies received automated reminders [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41]. Half of the program reminders were received at least once a week [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41], and the remaining were sent on an ad hoc basis [Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30] or participants were able to personalize whether they received notifications or not [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30]. Other program features used to encourage adherence included the ability to personalize mindfulness course content (4/14, 29%) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Chien I, Enrique A, Palacios J, Regan T, Keegan D, Carter D, et al. A machine learning approach to understanding patterns of engagement with internet-delivered mental health interventions. JAMA Netw Open 2020 Jul 01;3(7):e2010791 [FREE Full text] [CrossRef] [Medline]25,Moher D, Liberati A, Tetzlaff J, Altman DG, PRISMA Group. Preferred reporting items for systematic reviews and meta-analyses: the PRISMA statement. J Clin Epidemiol 2009 Oct;62(10):1006-1012. [CrossRef] [Medline]26,Covidence. Veritas Health Innovation Ltd, Australia.   URL: https://www.covidence.org/ [accessed 2020-07-08] 28], homework activities (3/14, 21%) [Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38], self-reflections (2/14, 14%) [Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42], social contact (3/14, 21%) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33], personalization of app appearance (2/14, 14%) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24], lesson summaries (1/14, 7%) [Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38], progress tracking of mindfulness practice (1/14, 7%)[Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24], immediate feedback on practice (1/14, 7%) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5], demonstration videos (1/14, 7%) [Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39], goal setting (1/14, 7%) [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24], tracking psychological outcomes (1/14, 7%) [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24], and tracking physical health (1/14, 7%) [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24] (Table S4 in

Multimedia Appendix 1

Study demographics, examples of search strategy, and adherence, retention, and engagement strategies and outcomes.

DOCX File , 53 KBMultimedia Appendix 1) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37-Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43].

Contact initiated by facilitators or program reminders was most commonly delivered by email (9/14, 64%) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36-Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40-Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42] or telephone (7/14, 50%) [Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33-Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43].

Adherence

Nearly two-thirds (12/19, 63%) of the studies provided a definition of program adherence [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36-Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]. When defined as the percentage of program completion, the definitions of adherence varied between 50% and 100% program completion across studies. When adherence was grouped, the highest group of completion varied from 50% to 100% among the studies. A total of 6 (32%) studies did not provide a measurement for adherence and analyzed program use descriptively [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35]. Moreover, 1 (5%) study did not report adherence or program use [Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43]. The percentage of people who complied with the authors’ definitions of adherence ranged from 27% to 79%, with a mean compliance of 56% (SD 15%).

The Impact of Engagement Strategies on Adherence

Among studies that used only program features (n=8) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39-Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41], 4 recorded adherence between 50% and 72% (mean 58%, SD 8%) [Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39-Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41] (Table S3 in

Multimedia Appendix 1

Study demographics, examples of search strategy, and adherence, retention, and engagement strategies and outcomes.

DOCX File , 53 KBMultimedia Appendix 1). Among studies that used only facilitator-led strategies (n=5) [Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34-Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43], only 1 reported adherence of 27% [Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36]. Among studies that used a combination of program features and facilitator-led strategies (n=6) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42], 7 recorded adherence between 39% and 79% (mean 59%, SD 13) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42].

When examining studies that used program features, of the studies that used 1 strategy (n=6) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39-Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42], 5 measured adherence rates between 50% and 72% (mean 58%, SD 8%). Of the studies that used 2 strategies (n=8) [Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38], 3 measured adherence between 56% and 79% (mean 67%, SD 9%). A total of 5 studies did not include any engagement strategies within their program [Linardon J, Fuller-Tyszkiewicz M. Attrition and adherence in smartphone-delivered interventions for mental health problems: a systematic and meta-analytic review. J Consult Clin Psychol 2020 Jan;88(1):1-13. [CrossRef] [Medline]15,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34-Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43], and 2 [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24] used ≥5 strategies; adherence was only recorded in 2 of these studies, and they were below 40%. Studies that involved only program reminders as engagement strategies (n=4, 3 studies recorded adherence) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41] had an average adherence rate of 54% (SD 3%) compared with the average adherence rate of 48% (SD 8%) of those studies that used reminders and other strategies (n=4, only 2 recorded adherence) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32], and the average adherence rate of 69% of those studies that did not use program reminders but only used other strategies (n=6, 4 recorded adherence) [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37-Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42].

How Adherence Affected Outcomes

A total of 10 (53%) studies analyzed the relationship between outcome variables and adherence [Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38-Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]. Of them, 4 studies found that people who had higher adherence to mindfulness programs had a significantly higher improvement in outcomes [Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]; 1 study found that people with higher scores for depression at baseline were less likely to be adherent or complete mindfulness programs [Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39]; 1 found that people with higher blood pressure readings were more likely to be compliant [Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14]; and 1 showed that higher quality of life scores at baseline were significantly associated with improved adherence [Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32]. A total of 3 studies found no relationship between baseline scores and adherence or adherence and outcome variables [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38].

Financial Compensation and Program Adherence

Of the 6 studies that provided any type of compensation, 2 measured adherence with a mean of 42% (SD 15%; range 27-56) [Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36]. Among the studies that did not offer financial compensation, the majority (8/13, 62%) measured adherence with a mean of 60% (SD 11%; range 39-79) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37-Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42].

Intervention Length and Program Adherence

The impact of the intervention length on adherence was analyzed. Of the 5 studies with an intervention <8 weeks, none recorded adherence. Those with an 8-week intervention recorded an average of 58% (SD 16%) adherence (6/10, 60% of the studies measured adherence) [Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]; those with interventions >8 weeks recorded an average of 52% (SD 9%) adherence (4/4, 100% of the studies measured adherence) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41].

Retention

Most (10/19, 53%) studies conducted pre-post analysis with additional follow-up points [Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32-Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]. Follow-up periods ranged from 4 to 36 weeks after intervention, and the most frequent follow-up time was 12 weeks after the intervention (3/10, 30%) [Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]. After intervention, most (14/19, 74%) studies had over 70% retention (mean 78%, SD 15%; range 35%-100%) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33-Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43]. At the last follow-up point, 4 studies had retention above 70% [Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38].

The Impact of Engagement Strategies on Retention

Studies that applied only facilitator-led strategies, on average, were 6 weeks in duration (SD 2; range 2-8) and had a retention rate of 93% (SD 10; range 73-100) compared with studies with a combination of program features and facilitator-led strategies with a mean duration of 16 weeks (SD 10; range 8-52) and a retention rate of 75% (SD 5%; range 69-84) and those with only program features with a mean duration of 8 weeks (SD 2; range 4-12) and retention rate of 67% (SD 15%; range 30-79).

Of the studies that used facilitator-led strategies only, 40% (2/5) had follow-up periods after postintervention follow-up [Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36]. On average, follow-up was 7 (range 6-8) weeks and retention was 76% (SD 15%; range 69-82). Of the 6, 5 (50%) studies using a combination of program features and facilitator-led strategies had long-term follow-up, which, on average, was 11 weeks (SD 0.9; range 10-12), with a retention rate of 71% (SD 15; range 49-83) [Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]. Of the 8, 5 (63%) studies using program features only also had a long-term follow-up period of, on average, 13 (range 4-36) weeks, with retention rates of 53% (SD 18; range 20-74) [Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39].

Studies that used only program reminders as engagement strategies (n=4) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41] had mean retention rates of 71% after intervention (n=3) [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41] and retention of 74% at the last follow-up point (n=1) [Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14]. Studies that used reminders and other strategies (n=4) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32] had a mean retention of 78% after intervention (n=3) [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30] and 57% at the last follow-up point (n=2) [Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32]. Studies that did not use program reminders but only used other strategies (n=8) [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37-Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42] had a mean retention of 67% after intervention (n=6) [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37-Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42] and 58% at the last follow-up point (n=5) [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42].


Principal Findings

In this review, we described the engagement strategies applied to web-based mindfulness programs and their impact on adherence rates. The use of program features only was associated with program adherence but not with maintaining study retention. Engagement strategies were largely reminders to use the program and, to a lesser extent, the ability to customize program content, interact with features, or engage with content on a deeper level through reflections, homework activities, and discussions of content with facilitators. There was little difference between the type of engagement strategy used and adherence to programs or retention rates.

The need to accurately report study and program attrition to better understand the associations between program adherence and health outcomes has been established [Eysenbach G. The law of attrition. J Med Internet Res 2005;7(1):e11 [FREE Full text] [CrossRef] [Medline]11,Sieverink F, Kelders SM, van Gemert-Pijnen JE. Clarifying the concept of adherence to eHealth technology: systematic review on when usage becomes adherence. J Med Internet Res 2017 Dec 06;19(12):e402 [FREE Full text] [CrossRef] [Medline]12]. Our review found variability across studies in adherence measurements and inconsistencies in reporting adherence. Some studies measured adherence as completing a specific percentage of the program [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39,Younge JO, Wery MF, Gotink RA, Utens EM, Michels M, Rizopoulos D, et al. Web-based mindfulness intervention in heart disease: a randomized controlled trial. PLoS One 2015;10(12):e0143843 [FREE Full text] [CrossRef] [Medline]41]. Other studies described adherence by grouping the number of sessions completed [Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Thompson NJ, Patel AH, Selwa LM, Stoll SC, Begley CE, Johnson EK, et al. Expanding the efficacy of Project UPLIFT: distance delivery of mindfulness-based depression prevention to people with epilepsy. J Consult Clin Psychol 2015 Apr;83(2):304-313 [FREE Full text] [CrossRef] [Medline]33,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Kladnitski N, Smith J, Uppal S, James MA, Allen AR, Andrews G, et al. Transdiagnostic internet-delivered CBT and mindfulness-based treatment for depression and anxiety: a randomised controlled trial. Internet Interv 2020 Apr;20:100310 [FREE Full text] [CrossRef] [Medline]38,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42] or by describing use [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29,Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Rosen KD, Paniagua SM, Kazanis W, Jones S, Potter JS. Quality of life among women diagnosed with breast Cancer: a randomized waitlist controlled trial of commercially available mobile app-delivered mindfulness training. Psychooncology 2018 Aug 01;27(8):2023-2030. [CrossRef] [Medline]32,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Wahbeh H, Goodrich E, Oken B. Internet-based mindfulness meditation for cognition and mood in older adults: a pilot study. Altern Ther Health Med 2016;22(2):44-53 [FREE Full text] [Medline]35]. Although findings suggest that program adherence is similar between interventions using program features only and those using a combination of program features and facilitator-led strategies, these results should be interpreted with caution because of the variability in reporting. The variability in measuring adherence is consistent in the e-therapy literature [Donkin L, Christensen H, Naismith SL, Neal B, Hickie IB, Glozier N. A systematic review of the impact of adherence on the effectiveness of e-therapies. J Med Internet Res 2011 Aug;13(3):e52 [FREE Full text] [CrossRef] [Medline]44] and limits the ability to assess the relationships between adherence to and engagement with web-based interventions and user outcomes. Future studies should consider reporting adherence as a percentage of program completion for easier comparisons across studies.

Similarly, the ability to measure the impact of engagement strategies on study attrition is limited. The findings suggest that studies using only facilitator-led strategies were favorable for maintaining study retention [Lindsay EK, Young S, Smyth JM, Brown KW, Creswell JD. Acceptance lowers stress reactivity: dismantling mindfulness training in a randomized controlled trial. Psychoneuroendocrinology 2018 Jan;87:63-73. [CrossRef] [Medline]31,Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34-Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43]. On average, at the postintervention measurement, studies with only facilitator-led strategies had a retention rate of 93% (SD 10%) compared with the rate of those using only program features of 67% (SD 15%). Similar findings were observed during the follow-up period (76%, SD 7% vs 53%, SD 18%a). However, there is limited evidence as to whether the presence of the facilitator was the reason for this variability or whether other factors such as intervention length, follow-up length, or demographic characteristics of participants contributed to attrition. For example, 1 study that used only program features to improve engagement had low retention after intervention (35%) and at the 8-week follow-up (20%) [Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24]. No information was provided regarding the reason for these high attrition rates, making it difficult to determine the cause of these findings. The use of a facilitator or therapist to guide web-based psychological programs has been debated [Fish J, Brimson J, Lynch S. Mindfulness interventions delivered by technology without facilitator involvement: what research exists and what are the clinical outcomes? Mindfulness (N Y) 2016 Jun;7(5):1011-1023 [FREE Full text] [CrossRef] [Medline]45,Saddichha S, Al-Desouki M, Lamia A, Linden IA, Krausz M. Online interventions for depression and anxiety - a systematic review. Health Psychol Behav Med 2014 Jan 1;2(1):841-881 [FREE Full text] [CrossRef] [Medline]46]. Studies of cognitive behavioral therapy interventions found that the presence of a therapist as a facilitator improved symptoms of depression compared with interventions with no facilitator [Saddichha S, Al-Desouki M, Lamia A, Linden IA, Krausz M. Online interventions for depression and anxiety - a systematic review. Health Psychol Behav Med 2014 Jan 1;2(1):841-881 [FREE Full text] [CrossRef] [Medline]46]. However, improvements in anxiety symptoms were similar across studies [Saddichha S, Al-Desouki M, Lamia A, Linden IA, Krausz M. Online interventions for depression and anxiety - a systematic review. Health Psychol Behav Med 2014 Jan 1;2(1):841-881 [FREE Full text] [CrossRef] [Medline]46], and no information was provided about whether the presence of a facilitator affected adherence. Improvements in patient outcomes may also be explained by the presence of comorbidities, including physical and mental illnesses, on which mindfulness may have a positive impact [Alsubaie M, Abbott R, Dunn B, Dickens C, Keil TF, Henley W, et al. Mechanisms of action in mindfulness-based cognitive therapy (MBCT) and mindfulness-based stress reduction (MBSR) in people with physical and/or psychological conditions: a systematic review. Clin Psychol Rev 2017 Jul;55:74-91. [CrossRef] [Medline]47]. Therefore, participation in a mindfulness program targeting 1 disease may have additional benefits for other comorbid conditions. Furthermore, studies that used only facilitator-led strategies experienced, on average, a higher retention rate, which is similar to previous reviews that have described that self-directed interventions often require low levels of support from facilitators [Russell L, Ugalde A, Milne D, Austin D, Livingston PM. Digital characteristics and dissemination indicators to optimize delivery of internet-supported mindfulness-based interventions for people with a chronic condition: systematic review. JMIR Ment Health 2018 Aug 21;5(3):e53 [FREE Full text] [CrossRef] [Medline]16]. The use of facilitators to encourage adherence, or therapists to deliver content, needs to be weighed against the sustainability goals, cost of the program and length of the intervention during trials, and potential scaling after implementation.

Most studies in this review showed that web-based mindfulness resulted in improvements in either psychological or physiological outcome measures [Russell L, Ugalde A, Orellana L, Milne D, Krishnasamy M, Chambers R, et al. A pilot randomised controlled trial of an online mindfulness-based program for people diagnosed with melanoma. Support Care Cancer 2019 Jul 30;27(7):2735-2746. [CrossRef] [Medline]3,Chandler J, Sox L, Diaz V, Kellam K, Neely A, Nemeth L, et al. Impact of 12-month smartphone breathing meditation program upon systolic blood pressure among non-medicated stage 1 hypertensive adults. Int J Environ Res Public Health 2020 Mar 17;17(6):1955 [FREE Full text] [CrossRef] [Medline]5,Gotink RA, Younge JO, Wery MF, Utens EM, Michels M, Rizopoulos D, et al. Online mindfulness as a promising method to improve exercise capacity in heart disease: 12-month follow-up of a randomized controlled trial. PLoS One 2017;12(5):e0175923 [FREE Full text] [CrossRef] [Medline]14,Moberg C, Niles A, Beermann D. Guided self-help works: randomized waitlist controlled trial of Pacifica, a mobile app integrating cognitive behavioral therapy and mindfulness for stress, anxiety, and depression. J Med Internet Res 2019 Jun 08;21(6):e12556 [FREE Full text] [CrossRef] [Medline]24,Huberty J, Green J, Glissmann C, Larkey L, Puzia M, Lee C. Efficacy of the mindfulness meditation mobile app "Calm" to reduce stress among college students: randomized controlled trial. JMIR Mhealth Uhealth 2019 Jun 25;7(6):e14273 [FREE Full text] [CrossRef] [Medline]29-Wahbeh H. Internet Mindfulness Meditation Intervention (IMMI) improves depression symptoms in older adults. Medicines (Basel) 2018 Nov 02;5(4):119 [FREE Full text] [CrossRef] [Medline]34,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Compen F, Bisseling E, Schellekens M, Donders R, Carlson L, van der Lee M, et al. Face-to-face and internet-based mindfulness-based cognitive therapy compared with treatment as usual in reducing psychological distress in patients with cancer: a multicenter randomized controlled trial. J Clin Oncol 2018 Aug 10;36(23):2413-2421. [CrossRef]37,Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39-Tavallaei V, Rezapour-Mirsaleh Y, Rezaiemaram P, Saadat SH. Mindfulness for female outpatients with chronic primary headaches: an internet-based bibliotherapy. Eur J Transl Myol 2018 Apr 24;28(2):7380 [FREE Full text] [CrossRef] [Medline]43]. Two key findings from this review further highlighted the relationship between study retention and baseline functioning of participants, where those with poorer psychological well-being at baseline were more likely to drop out [Hearn JH, Finlay KA. Internet-delivered mindfulness for people with depression and chronic pain following spinal cord injury: a randomized, controlled feasibility trial. Spinal Cord 2018 Aug;56(8):750-761. [CrossRef] [Medline]39], and those with higher adherence were more likely to experience greater improvements in outcomes [Kubo A, Kurtovich E, McGinnis M, Aghaee S, Altschuler A, Quesenberry C, et al. A randomized controlled trial of mHealth mindfulness intervention for cancer patients and informal cancer caregivers: a feasibility study within an integrated health care delivery system. Integr Cancer Ther 2019;18:1534735419850634 [FREE Full text] [CrossRef] [Medline]30,Bostock S, Crosswell AD, Prather AA, Steptoe A. Mindfulness on-the-go: effects of a mindfulness meditation app on work stress and well-being. J Occup Health Psychol 2019 Feb;24(1):127-138 [FREE Full text] [CrossRef] [Medline]36,Henriksson J, Wasara E, Rönnlund M. Effects of eight-week-web-based mindfulness training on pain intensity, pain acceptance, and life satisfaction in individuals with chronic pain. Psychol Rep 2016 Dec;119(3):586-607. [CrossRef] [Medline]40,Stjernswärd S, Hansson L. Effectiveness and usability of a web-based mindfulness intervention for caregivers of people with mental or somatic illness. A randomized controlled trial. Internet Interv 2018 Jun;12:46-56 [FREE Full text] [CrossRef] [Medline]42]. This is similar to previous findings where higher levels of worry and rumination at baseline resulted in disengagement from mindfulness-based interventions [Banerjee M, Cavanagh K, Strauss C. Barriers to mindfulness: a path analytic model exploring the role of rumination and worry in predicting psychological and physical engagement in an online mindfulness-based intervention. Mindfulness (N Y) 2018 Nov 6;9(3):980-992 [FREE Full text] [CrossRef] [Medline]23]. Stricter measurements of adherence are required in future studies to fully understand the role of adherence in the success of interventions.

Program features applied throughout studies to enhance engagement varied according to the type and number of features available to users. Furthermore, the number and type of features included had similar impacts on program adherence and study retention, suggesting that there may not be one superior feature to be included in programs. Features such as diaries, reminders, and social connectedness are commonly used in interventions as behavior change techniques [Abraham C, Michie S. A taxonomy of behavior change techniques used in interventions. Health Psychol 2008 May;27(3):379-387. [CrossRef] [Medline]21], and web-based features have been shown to be successful in improving user outcomes in other e-interventions [Riva S, Camerini A, Allam A, Schulz PJ. Interactive sections of an internet-based intervention increase empowerment of chronic back pain patients: randomized controlled trial. J Med Internet Res 2014;16(8):e180 [FREE Full text] [CrossRef] [Medline]48]. Within mindfulness, more specific reporting is needed to assess how often users engage with each type of feature to determine the relationship among engagement strategies, adherence, and outcomes.

Limitations

Across studies, there was a large variance in interventions and in reporting adherence. These factors made it difficult to draw any firm conclusions from the data.

The sample of the included studies was predominately White and female, which limits the generalizability of these findings to other population groups.

This review aims to describe the influence of engagement strategies on adherence and retention among people living with chronic illnesses or conditions. Other studies measuring adherence to mindfulness in the general population may have provided additional information on the impact of engagement strategies. However, there is a need to evaluate engagement and adherence to web-based interventions, specifically in people living with chronic illness. People with chronic illness may be more likely to experience depression and anxiety symptoms than those without a chronic illness [Parks AC, Williams AL, Kackloudis GM, Stafford JL, Boucher EM, Honomichl RD. The effects of a digital well-being intervention on patients with chronic conditions: observational study. J Med Internet Res 2020 Jan 10;22(1):e16211 [FREE Full text] [CrossRef] [Medline]49]. Lower mental well-being can affect the use of and engagement with web-based interventions.

Furthermore, the primary outcome of the review was to assess adherence, retention, and engagement strategies rather than to draw conclusions about the effectiveness of interventions on patient outcomes. As a result, the risk of bias assessment was less relevant.

Conclusions

Engagement strategies in web-based mindfulness programs largely comprise reminders to use the program. The impact of other features such as personalization, self-reflection activities, and lesson summaries on adherence requires further investigation. There is variance in the way adherence is measured, and intervention lengths and follow-up periods are inconsistent. More thorough reporting and a standardized framework for measuring adherence are needed to more accurately assess adherence and engagement strategies.

Conflicts of Interest

None declared.

Multimedia Appendix 1

Study demographics, examples of search strategy, and adherence, retention, and engagement strategies and outcomes.

DOCX File , 53 KB

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RCT: randomized controlled trial


Edited by R Kukafka; submitted 29.04.21; peer-reviewed by H Wahbeh, H Haskelberg; comments to author 18.06.21; revised version received 09.08.21; accepted 12.09.21; published 12.01.22

Copyright

©Natalie Winter, Lahiru Russell, Anna Ugalde, Victoria White, Patricia Livingston. Originally published in the Journal of Medical Internet Research (https://www.jmir.org), 12.01.2022.

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