Abstract
BACKGROUND: Digital health interventions (DHIs) harness technological innovation to address challenges in the accessibility and scalability of health care. However, the effectiveness of DHIs is challenged by low user engagement and adherence, as users tend to drop out over time. The supportive accountability model (SAM) is a theoretical framework designed to enhance adherence to DHIs by incorporating structured human support. OBJECTIVE: Guided by SAM, this scoping review answers the following research questions: (1) What is the extent of research on human support factors and their influence on engagement with and adherence to DHIs? and (2) What is the extent of research applying SAM (ie, accountability, bond, and legitimacy) to improve engagement with and adherence to DHIs? METHODS: Our search strategy followed the PRISMA-ScR (Preferred Reporting Items for Systematic Reviews and Meta-Analyses Extension for Scoping Reviews). We conducted our literature search using 6 databases selected based on relevance to our research topic: MEDLINE, PsycINFO, Embase, CINAHL, Scopus, and ClinicalTrials.gov. Search terms included ("human support" OR "supportive accountability") AND (engagement OR adherence) AND intervention, applied to titles, abstracts, and keywords. Hand-searching was also used to identify additional relevant articles. Two authors (SPYC and GK) screened articles in multiple rounds using predefined inclusion and exclusion criteria. The final sample consisted of 36 empirical, peer-reviewed articles published in scholarly journals. All articles examined human-supported DHIs. RESULTS: Implementation of human support among the interventions varied by the source, delivery method, and frequency and duration of support. Overall, there were inconsistencies in the application of SAM to intervention designs. Support was provided by 4 main groups: peers and peer specialists, health experts and practitioners, trained coaches, and members of the research study team. Modes of communication included phone or video calls, as well as text-based support, such as messaging or email. The frequency and duration of support varied across studies and were influenced by the communication method used, with more structured and frequent contact occurring in interventions that relied on synchronous support, such as phone or video calls. In addition, we found that some studies used human support as the primary mode of intervention delivery rather than as an adjunctive tool, focusing on improving engagement and adherence, as proposed by SAM. Aside from accountability, there was also a lack of explicit focus on other constructs within the model (eg, bond and legitimacy). CONCLUSIONS: This scoping review highlights the current use of human support to promote DHI adherence and reveals gaps in the application of SAM. Future research should address all core SAM components-not just accountability-and ensure human support is used as an adjunct to enhance engagement. These steps can help maximize the impact of DHIs on health care access and outcomes.