King's College London

Background: Multi-parametric remote measurement technologies (RMTs) comprise smartphone applications and wearable devices for both active and passive symptom tracking. They hold great potential for understanding current, and predicting future, depression status. However, the promise of using RMTs for relapse prediction is heavily dependent on user engagement, defined as both a behavioral and experiential construct. A better understanding of how to promote engagement in RMT research through various in-app components will aid in providing scalable solutions for future remote research, higher quality results and applications for implementation into clinical practice.

Objectives: To provide the rationale and protocol for a two-armed, randomized controlled trial to investigate the effect of insightful notifications, progress visualization and researcher contact details on behavioral and experiential engagement with a multi-parametric mHealth data collection platform- RADAR-base.

Methods: The study aims to recruit a total of 140 participants upon completion of their participation in the Remote Assessment of Disease and Relapse- Major Depressive Disorder (RADAR-MDD) study London site. Data will be collected via three weekly tasks through an active smartphone app, a passive (background) data collection app, and a Fitbit device. Participants will be randomly allocated at a 1:1 ratio to receive either (A) an adapted version of the active app that incorporates insightful notifications, progress visualization and access to researcher contact details; or (B) the active app as usual. Statistical tests will test the hypotheses that participants using the adapted app will complete a higher percentage of weekly tasks (behavioral engagement; primary outcome) and score higher on self-awareness measures (experiential engagement).

Results: Recruitment commenced in April 2021. Data collection will be completed in September 2021. The results of this study will be communicated via publication in early 2022.

Conclusions: This study aims to understand how best to promote engagement with RMTs in depression research. Findings will help determine the most effective techniques for implementation into both future rounds of the RADAR-MDD study and, in the longer-term, clinical practice.

Trial registration: NCT04972474