Financial Incentives and Treatment Outcomes in Adolescents With Severe Obesity: A Randomized Clinical Trial.

Importance: Adolescent severe obesity is usually not effectively treated with traditional lifestyle modification therapy. Meal replacement therapy (MRT) shows short-term efficacy for body mass index (BMI; calculated as weight in kilograms divided by height in meters squared) reduction in adolescents, and financial incentives (FIs) may be an appropriate adjunct intervention to enhance long-term efficacy.

Objective: To evaluate the effect of MRT plus FIs vs MRT alone on BMI, body fat, and cardiometabolic risk factors in adolescents with severe obesity.

Design, setting, and participants: This was a randomized clinical trial of MRT plus FIs vs MRT alone at a large academic health center in the Midwest conducted from 2018 to 2022. Participants were adolescents (ages 13-17 y) with severe obesity (≥120% of the 95th BMI percentile based on sex and age or ≥35 BMI, whichever was lower) who were unaware of the FI component of the trial until they were randomized to MRT plus FIs or until the end of the trial. Study staff members collecting clinical measures were blinded to treatment condition. Data were analyzed from March 2022 to February 2024.

Interventions: MRT included provision of preportioned, calorie-controlled meals (~1200 kcals/d). In the MRT plus FI group, incentives were provided based on reduction in body weight from baseline.

Main outcomes and measures: The primary end point was mean BMI percentage change from randomization to 52 weeks. Secondary end points included total body fat and cardiometabolic risk factors: blood pressure, triglyceride to high-density lipoprotein ratio, heart rate variability, and arterial stiffness. Cost-effectiveness was additionally evaluated. Safety was assessed through monthly adverse event monitoring and frequent assessment of unhealthy weight-control behaviors.

Results: Among 126 adolescents with severe obesity (73 female [57.9%]; mean [SD] age, 15.3 [1.2] years), 63 participants received MRT plus FIs and 63 participants received only MRT. At 52 weeks, the mean BMI reduction was greater by -5.9 percentage points (95% CI, -9.9 to -1.9 percentage points; P = .004) in the MRT plus FI compared with the MRT group. The MRT plus FI group had a greater reduction in mean total body fat mass by -4.8 kg (95% CI, -9.1 to -0.6 kg; P = .03) and was cost-effective (incremental cost-effectiveness ratio, $39 178 per quality-adjusted life year) compared with MRT alone. There were no significant differences in cardiometabolic risk factors or unhealthy weight-control behaviors between groups.

Conclusions and relevance: In this study, adding FIs to MRT resulted in greater reductions in BMI and total body fat in adolescents with severe obesity without increased unhealthy weight-control behaviors. FIs were cost-effective and possibly promoted adherence to health behaviors.

Trial registration: ClinicalTrials.gov Identifier: NCT03137433.