Long-term adherence to a wearable for continuous behavioural activity measuring in the SafeHeart implantable cardioverter defibrillator population.

Aims: Wearable health technologies are increasingly popular. Yet, wearable monitoring only works when devices are worn as intended, and adherence reporting lacks standardization. In this study, we aimed to explore the long-term adherence to a wrist-worn activity tracker in the prospective SafeHeart study and identify patient characteristics associated with adherence.
Methods and Results: This study enrolled 303 participants, instructed to wear a wrist-worn accelerometer day and night for 6 months. Long-term adherence was defined as valid days (≥22 h of wear time) divided by expected days, and daily adherence as mean hours of wear time per 24 h period. Optimal, moderate, and low long-term and daily adherence groups were defined as long-term adherence above or below 95 and 75% and daily adherence above or below 90 and 75%. Regression models were used to identify patient characteristics associated with long-term adherence. In total, 296 participants [median age 64 years; interquartile range (IQR) 57-72; 19% female] were found eligible, yielding 44 003 days for analysis. The median long-term adherence was 88.2% (IQR 74.6-96.5%). A total of 83 (28%), 127 (42.9%), and 86 (29.1%) participants had optimal, moderate, and low long-term adherence, and 163 (55.1%), 87 (29.4%), and 46 (15.5%) had optimal, moderate, and low daily adherence, respectively. Age and smoking habits differed significantly between adherence levels, and increasing changeover intervals improved the degree of long-term adherence.
Conclusion: Long-term adherence to a wearable activity tracker was 88.2% over a 6-month period. Older age and longer changeover interval were positively associated with long-term adherence. This serves as a benchmark for future studies that rely on wearable devices.
Trial Registration Number: The National Trial Registration number: NL9218 (https://onderzoekmetmensen.nl/).
Competing Interests: Conflict of interest: H.L.T., R.K., T.O.A., J.H.S., F.V.Y.T., and J.L. received funding for the SafeHeart study through the EUROSTARS PROJECT E! 113994 Horizon 2020 grant. T.O.A. is a co-founder of Vital Beats and has stock ownership. T.O.A. is the co-author of a pending patent application that is within the field of this study. J.L. is an employee and shareholder of Activinsights Ltd, the manufacturers of the behavioral assessment wearable used in the study. F.V.Y.T. received consulting honoraria (no personal gain) from Boston Scientific and Abbott. J.H.S. received research grants from Medtronic outside this study, and speaker fee and consultancy fee from Medtronic and Vital Beats. S.Z.D. is a consultant for Vital Beats. D.M.F. and M.Z.H.K. declare no conflicts of interest.
(© The Author(s) 2024. Published by Oxford University Press on behalf of the European Society of Cardiology.)