Development and exploratory analysis of a multi-dimensional metric of adherence for digital health interventions

IntroductionAdherence is often cited as an important metric to demonstrate sustained engagement of an individual or population with a health technology, but its definition is often ill-defined. Any adherence definition made for digital health interventions must be clearly defined to ensure a consistent approach to measuring sustained use as an indicator of impact. MethodsThis study followed mathematically-defined definitions of distinct aspects of adherence: initial adoption, consistency, duration, and dropout. These were then applied to a digital physiotherapy dataset of older adults (N=56). Participants were assigned 3 sessions a week of exergames (exercise-based videogames) for 12 weeks using MIRA rehab software platform. ResultsThe following adherence characteristics emerged: an initial dropout of 3% (completed [≤]3 sessions), 20% of participants achieving the desired consistency ([≥]3 sessions a week for 12 weeks), 39% of participants passing a duration threshold (completing [≥]20 minutes a week for 12 weeks), and an average dropout at 72.3% (when judged by percentage of sessions completed at dropout). ConclusionThe approach used for measuring and reporting adherence metrics allows readers to draw clear conclusions about the different aspects of engagement that users displayed with the digital health programme. This type of reporting is recommended for all future digital health studies reporting adherence measures to ensure a consistent approach to reporting and comparing digital health interventions and their impact.