Contemp Clin Trials Commun
Background: Nonadherence to study protocols reduces the generalizability, validity, and statistical power of longitudinal studies.
Purpose: To determine whether an automated electronically-delivered regret lottery would improve adherence to an intensive mHealth self-monitoring protocol as part of a longitudinal observational study.
Methods: We enrolled 77 adults into a 52-week study requiring five daily ecologic momentary assessments (EMA) of stress and daily accelerometer use. We performed a pre/post single-arm study to evaluate the efficacy of a lottery intervention in improving adherence to this protocol. Midway through the study, participants were invited to enter a weekly regret lottery ($50 prize, expected value
Results: 62 participants consented to lottery participation. In the 12 weeks prior to lottery initiation, weekly adherence was declining (slope -1.4%/week). The weekly per-participant probability of adherence was higher after lottery initiation when comparing the 4-week (32% pre-lottery vs 50% post-lottery, p < 0.001), 8-week (37% vs 49%, p < 0.001), and 12-week periods (39% vs 45%, p = 0.001) before and after lottery initiation. However, the rate of decline in adherence over time was unchanged.
Conclusion: The implementation of an automated, electronically-delivered weekly regret lottery improved adherence with an intensive self-monitoring study protocol. Regret lotteries may represent a cost-effective tool to improve adherence and reduce bias caused by dropout or nonadherence.
School of Medicine
General Internal Medicine