Cost-effectiveness of goal-directed and outcome-based financial incentives for weight loss in low-income populations: the FIReWoRk randomized clinical trial

Background: The Financial Incentives for Weight Reduction (FIReWoRk) clinical trial showed that financial incentive weight-loss strategies designed using behavioral economics were more effective than provision of weight-management resources only. We now evaluate cost-effectiveness. Methods: Cost-effectiveness analysis of a multisite randomized trial enrolling 668 participants with obesity living in low-income neighborhoods. Participants were randomized to (1) goal-directed incentives (targeting behavioral goals), (2) outcome-based incentives (targeting weight-loss), and (3) resources only, which were provided to all participants and included a 1-year commercial weight-loss program membership, wearable activity monitor, food journal, and digital scale. We assessed program costs, time costs, quality of life, weight, and incremental cost-effectiveness in dollars-per-kilogram lost. Results: Mean program costs at 12 months, based on weight loss program attendance, physical activity participation, food diary use, self-monitoring of weight, and incentive payments was $1271 in the goal-directed group, $1194 in the outcome-based group, and $834 in the resources-only group (difference, $437 [95% CI, 398 to 462] and $360 [95% CI, 341–363] for goal-directed or outcome-based vs resources-only, respectively; difference, $77 [95% CI, 58–130] for goal-directed vs outcome-based group). Quality of life did not differ significantly between the groups, but weight loss was substantially greater in the incentive groups (difference, 2.34 kg [95% CI, 0.53–4.14] and 1.79 kg [95% CI, −0.14 to 3.72] for goal-directed or outcome-based vs resources only, respectively; difference, 0.54 kg [95% CI, −1.29 to 2.38] for goal-directed vs outcome-based). Cost-effectiveness of incentive strategies based on program costs was $189/kg lost in the goal-directed group (95% CI, $124/kg to $383/kg) and $186/kg lost in the outcome-based group (95% CI, $113/kg to $530/kg). Conclusions: Goal-directed and outcome-based financial incentives were cost-effective strategies for helping low-income individuals with obesity lose weight. Their incremental cost per kilogram lost were comparable to other weight loss interventions.