The Heartline Experience

BACKGROUND: Digital health technologies can potentially improve clinical research efficiency and increase participant diversity but have challenges with long-term participant engagement. OBJECTIVES: The Heartline Study evaluated the impact of a mobile app-based heart health engagement program with the Irregular Rhythm Notification (IRN) and electrocardiogram features of the Apple Watch on diagnosis, treatment, and outcomes of atrial fibrillation in U.S. participants aged ≥65 years. METHODS: Participants were randomized 3:1 to the watch group (vs no watch control group), stratified by prevalent atrial fibrillation. Participants interfaced with the study via a custom, app-based engagement program designed to facilitate participant enrollment, post-IRN follow-up, and electronic patient-reported outcome (ePRO) collection. To ensure users would respond to app-based reminders to complete ePROs and follow-up with providers after a potential IRN, targeted engagement strategies based on behavioral science principles were incorporated, including human-centered design, curated health education, and points-based incentives. RESULTS: Of 34,244 enrolled Heartline participants, 32,299 (94%) started the program. High, longitudinal participant engagement was seen, with 93% actively engaged with the app at least weekly after 1 year, and 86% after 2 years. ePRO completion rates were 82% at 1 year and 76% at 2 years. Upon study completion, participants reported high satisfaction with the study and their personal investment. CONCLUSIONS: Study adherence in Heartline was high and sustained through 2-year follow-up, using a purposely designed engagement program delivered by a mobile app. Participants in this older population remotely and regularly submitted study information through the app and reported high study satisfaction (A Study to Investigate if Early Atrial Fibrillation [AF] Diagnosis Reduces Risk of Events Like Stroke in the Real-World; NCT04276441).