Assessing Patient Adherence to and Engagement With Digital Interventions for Depression in Clinical Trials: A Systematic Literature Review (Preprint)

Abstract

New approaches to the treatment of depression are necessary for patients who do not respond to current treatments or lack access to them due to geographical, social, or cost-related barriers. Digital interventions for depression are novel, however low patient engagement could limit their effectiveness.

This systematic literature review (SLR) assessed how patient adherence to and engagement with digital interventions for depression has been measured in the published literature, what levels of adherence and engagement have been reported, and whether higher adherence and increased engagement are linked to increased efficacy.

We focused on a patient population of adults aged 18 and older with depression or major depressive disorder (MDD) as the primary diagnosis and included clinical trials, feasibility studies, and pilot studies of digital interventions to treat depression, such as digital therapeutics and digital health (eg, mental health apps). We screened 756 unique records published between January 1, 2000 and April 15, 2022 and analyzed 94 that met the inclusion criteria.

The majority of the studies in this SLR were published in 2017 or after and encompassed results from 20,111 patients in studies using 47 unique web-based interventions (with an additional 10 web-based interventions that were not described by name in the studies), 15 mobile app interventions, 5 app-based interventions also accessible via the web, and 1 CD-ROM intervention. Adherence was most often measured as the percentage of patients who completed all available modules. Fewer than half (44.2%) of patients completed all modules; however, patients did finish 61.1% of the modules on average. Although patient engagement with digital interventions was measured in a variety of ways, the most common was the number of modules completed, with a mean of 6.4 (means ranged from 1.0 to 19.7 modules). The mean amount of time patients spent engaging with the interventions overall was 3.9 hours (means ranged from 0.7 to 8.4 hours). The majority of studies of web-based (75.6%) and app-based (88.9%) interventions found the intervention group had substantially greater improvement for at least 1 outcome compared with the control group (eg, care as usual, waitlist, active control). Nine of the 14 studies (64.3%) that investigated the relationship between engagement and patient outcomes found that increased engagement with the digital intervention was significantly associated with improved patient outcomes.

Patient adherence to and engagement with digital interventions for depression have been reported in the literature using a variety of metrics. Arriving at more standardized ways of reporting adherence and engagement would enable more effective comparisons across different digital interventions, studies, and populations.

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