Engagement with a remote symptom-tracking platform among participants with major depressive disorder (RADAR-Engage): a randomized controlled trial

Background:

Multi-parametric remote measurement technologies (RMTs), comprising smartphones and wearable devices, have the potential to revolutionise understanding of the etiology and trajectory of major depressive disorder (MDD). Engagement with RMTs in MDD research is of the upmost importance for validity of predictive analytical methods and long-term use, and can be conceptualized as both objective engagement (data availability) or subjective engagement (system usability and experiential factors). In-app components provide an opportunity to promote engagement with RMTs while minimizing research team resources. Randomized controlled trials (RCTs) are the gold standard in quantifying the effect of in-app components on engagement with RMTs in those with MDD.

Objective:

This study aimed to evaluate whether a multi-parametric RMT system with a visual progress report tracking data completion, theoretically informed notifications, and access to research team contact details could promote objective and subjective engagement with remote symptom tracking over and above the system as usual.

Methods:

A 2-arm, parallel-group RCT (participant-blinded) with 1:1 randomization was conducted with 100 participants with MDD over 12 weeks. Participants in both arms employed the RADAR-base system, involving a smartphone app for weekly symptom assessments and a wearable Fitbit device for continuous passive tracking. Participants in the intervention arm (n=50) also had access to the additional in-app components. The primary outcome was objective engagement with the system, measured as the percentage of weekly questionnaires during follow-up. Secondary outcomes comprised measures of subjective engagement (system engagement, system usability, and emotional self-awareness).

Results:

Levels of completion of the PHQ-9 task were similar in the control (69.2%) and intervention (68.1%) arms (p-value for difference between arms = 0.83, 95% CI -9.32 to 11.65). Those in the intervention group reported slightly higher user engagement (1.93, 95% CI -1.91 to 5.78), emotional self-awareness (1.13, 95% CI -2.93 to 5.19) and system usability (2.29, 95% CI -5.93 to 10.52) scores at follow-up, however all confidence intervals were wide and included 0.

Conclusions:

The adapted system did not increase objective or subjective engagement with remote symptom tracking in our research cohort. This study provides important foundations for understanding engagement with RMTs for research, and the methodologies by which this work can be replicated in both community and clinical settings. Clinical Trial: This study was registered as a clinical trial (reference number NCT04972474; https://clinicaltrials.gov/ct2/show/NCT04972474), and published as a protocol (https://doi.org/10.2196/32653).