A Randomized Trial of Incentives for Maintenance of Weight Loss

Background   Obesity rates around the world are increasing, with nearly 70% of US adults overweight or obese, leading to increased clinical and economic burden. While successful approaches for achieving weight loss have been identified, techniques for long-term maintenance of initial weight loss have largely been unsuccessful.  Financial incentive interventions have been shown in several settings to be successful in motivating subjects to adopt healthy behaviors, including initial weight loss. Conceptually, a behaviorally motivated lottery-based incentive might be more effective than ongoing repeated incentive payments; however, the comparative effectiveness of a lottery-based incentive, a traditional direct payment incentive, and a control of daily feedback without any incentive payment for weight loss maintenance is unknown.

Methods  191 participants were randomized in a 3-arm RCT in a 2:1 ratio for each active arm relative to control to either a lottery incentive worth an average of $3 a day, a direct payment of $3 a day, or daily feedback without any incentive payment. Eligible participants were those aged 30-80 who lost at least 5 kg during the first 4 months of participation in a national weight loss program. Participants received the intervention for 6 months (Phase I) and were followed for 6 additional months to examine efficacy following cessation of the intervention (Phase II).  The primary endpoint was weight change from baseline at the end of Phase I, with the change at the end of Phase II a key secondary endpoint. This is a pragmatic trial that recruited, consented, enrolled and followed patients electronically. Subjects were provided a wireless scale that transmits daily, self-monitored weights to the study database. Weights were verified every 3 months at a weight-loss center local to the participant and electronically transmitted.  We will use multiple imputation to fill in any missing data and keep the data arms blinded until the analytic approach is finalized.

 

Results Using the study web-based platform, 191 subjects were successfully randomized and in-person measurements were complete in 89% at the 6-month primary endpoint . Follow-ups are now complete and we will have the data fully analyzed by April, 2016.

 

Conclusion  This study has the potential to identify a practical and effective weight loss maintenance strategy, which could have both individual and group level benefits of reducing morbidity and economic costs by helping individuals maintain a healthier weight.