Defining and measuring engagement and adherence in digital mental health interventions: umbrella review protocol

Introduction

Digital Mental Health Interventions (DMHIs) hold significant promise in addressing mental health needs, particularly among marginalized populations with limited access to traditional mental health services.However, suboptimal engagement and adherence rates present ongoing challenges, limiting their potential impact. Despite the growing body of literature on DMHI engagement, there remains no consensus on how engagement and adherence are defined and measured across studies. This lack of uniformity complicates the evaluation of intervention effectiveness and the development of best practice guidelines. This umbrella review aims to synthesize existing evidence to identify how engagement and adherence are defined and measured in DMHIs and explore key factors influencing these measures.

Methods

The review objectives are guided by the PCC (Population, Concept, Context) framework. Following PRISMA-2020 guidelines and its extension for umbrella reviews, a systematic search will be conducted across Web of Science, CINAHL via EBSCO, MEDLINE via Ovid, PsycINFO via Ovid, Cochrane via EBM Reviews, and ProQuest Complete for systematic reviews, meta-analyses, and scoping reviews published in English over the past 10 years. An additional manual handsearching will be conducted on BMC Digital Health journal. Risk of bias will be assessed using the JBI Critical Appraisal Checklist for Systematic Reviews and Research Syntheses. The integration of quantitative and qualitative study findings will be conducted using a convergent mixed-methods approach to generate synthesized themes.

Results

Preliminary findings will provide a comprehensive summary of how engagement and adherence are defined across the literature, highlighting commonalities, inconsistencies, and gaps. The synthesis will outline the primary methods used to measure engagement (e.g., app usage metrics, self-reports, time spent on the platform) and adherence (e.g., module completion rates, frequency of logins). Additionally, the review will identify individual factors (e.g., age, mental health condition, digital literacy), technological factors (e.g., interface design, personalization features, gamification), and contextual factors (e.g., socioeconomic status, cultural considerations) that influence DMHI engagement and adherence.

Discussion

This umbrella review will enhance the understanding of engagement and adherence in DMHIs by synthesizing diverse definitions, measurement approaches, and influencing factors. It will identify key factors that support sustained user engagement, offering guidance for practitioners and app developers in creating more user-centered and effective interventions. The review will also propose best practice guidelines for defining, measuring, and reporting engagement and adherence, while outlining future research directions to improve user retention and optimize the effectiveness of DMHIs in enhancing mental health outcomes. Some anticipated challenges of this review include managing the large volume of search results and conducting a thorough yet efficient review, particularly given the rapidly evolving landscape of DMHI research. The search was conducted on March 6, 2025, resulting in 2,211 articles after removing duplicates. The protocol is registered with PROSPERO International prospective register of systematic reviews (CRD42025637603) and is available as a preprint on JMIR Research Protocols (10.2196/preprints.73438). This umbrella review is currently ongoing and is expected to be conducted over a 6-month period.