Initial Weight Status Moderates the Impact of Exercise Referral Schemes on Improving Patients' Body Mass Index

PurposeTo determine whether baseline body mass index (BMI) moderates BMI changes following completion of an exercise referral scheme (ERS).DesignRetrospective analysis.SettingData from the National ReferAll Database.Sample634 adults out of 39,283 (64% female; mean age 54 ± 15 years).InterventionParticipants completed a community-based ERS involving physical activity counseling and supervised exercise.MeasuresBMI was calculated as weight (kg) divided by height (m²) and participants were categorized by BMI: normal weight (<25.0 kg/m²), overweight (25.0-29.9 kg/m²), and obesity classes I (30.0-34.9 kg/m²), II (35.0-39.9 kg/m²), and III (≥40.0 kg/m²).AnalysisA 5 × 2 mixed methods analysis of covariance, adjusted for age, sex, ERS type, and follow-up duration examined BMI changes over time by group. Linear regression assessed the relation between baseline BMI and BMI change.ResultsBaseline BMI predicted BMI reduction (β = -0.07 ± 0.01, 95% CI: -0.09 to -0.04, P < .001). Compared to the normal weight group, individuals with obesity classes I-III had significantly greater reductions in BMI (mean difference range: 0.83-1.01 kg/m², all P < .001). No significant difference was observed between normal weight and overweight participants (P = .207).ConclusionThis study provides evidence that ERS can be effective in improving BMI outcomes among individuals who have an elevated initial BMI. These findings support the continued development and refinement of ERS as a scalable public health strategy to promote weight-related improvements.