The Effect of Periodic Email Prompts on Participant Engagement With a Behavior Change mHealth App: Longitudinal Study (Preprint)

Abstract

BACKGROUND Following the need for prevention of non-communicable diseases, mobile health (mHealth) apps are increasingly used for promoting lifestyle behavior changes. While mHealth apps have the potential to reach all population segments, providing accessible and personalized services, their effectiveness is often limited by low participant engagement and high attrition rates. OBJECTIVE The research question of this study concerns a large-scale, open access mHealth app focused on improving the lifestyle behaviors of its participants. This study examines whether periodic email prompts increase participant engagement with the mHealth app, and how this effect evolves over time. Points gained from activities in the app are used as an objective measure of participant engagement with the program. METHODS The data analyzed covers 22,797 participants over a period of 78 weeks. A Hidden Markov model (HMM) is employed for disentangling the over-time effects of periodic email prompts on participant engagement with the mHealth app, accounting for transitions between latent activity states. RESULTS The HMM indicates that participants are 70% of the time in the inactivity state – gaining zero points in total per week, 18% of the time in the average activity state – gaining 27 points per week, and 12% of the time in the high activity state – gaining 182 points per week. Receiving and opening a generic email is associated with a 3 percentage points increase in the likelihood of becoming active compared to the weeks when no email is received. CONCLUSIONS Participant engagement with a behavior change mHealth app can be positively influenced by email prompts, albeit to a limited extent. Given the relatively low costs associated with emails and the high population-reach that mHealth apps can achieve, such instruments can be a cost-effective means of increasing participant engagement in the stride towards improving program effectiveness.