Association Between Sociodemographic Characteristics and Weight Loss in a Financial Incentive Intervention for Adults With Obesity Living in Low-Income Neighborhoods

Abstract

Purpose

To evaluate the association between demographic characteristics and weight-loss in response to financial incentives designed using behavioral economics.

Design

Retrospective analysis of randomized clinical trial (RCT).

Setting

FIReWoRk RCT (NCT03157713), which found that financial incentives were more effective than provision of weight-management resources only for weight-loss.

Subjects

668 adults with obesity (221 in resources-only group, 447 in incentive groups) living in low-income neighborhoods.

Measures

Demographic characteristics and weight-loss.

Analysis

Linear mixed-effects models with interaction terms to examine effect of incentives on weight-loss in different demographic groups.

Results

Mean age of participants was 47.69 years, 81.0% were women, 72.6% were Hispanic, and mean BMI was 37.95 kg/m². Financial incentives increased percent weight loss at 6 months (difference in percent weight loss between financial incentive and resources-only group = −2.41%; 95% CI −3.23% to −1.58%). In fully adjusted models, participants who were Black lost less weight than participants who were White (difference in percent weight loss = 2.12%; 95% CI 0.25% to 3.99%). Differences in percent weight loss by sex, age, education and neighborhood income were absent. Models that tested for interactions between group assignment and percent weight loss did not demonstrate evidence of a heterogenous effect of incentives in sociodemographic subgroups.

Conclusion

Black participants in the FIReWoRk intervention lost less weight than White participants, but effectiveness of financial incentives generally did not vary significantly by sociodemographic characteristics. However, it remains important to evaluate potential impacts of financial incentive programs on health disparities.