Lifestyle interventions in a healthcare setting are effective for weight loss, but it is unclear whether more expensive interventions result in more weight loss. Our objective was to explore the relationship between intervention costs and effectiveness in a systematic review of randomized trials.
Intervention studies were selected from 14 reviews and from a systematic MEDLINE-search. Studies had to contain a dietary and a physical activity component and report data on measured weight loss in healthy Caucasian overweight adults. Intervention costs were calculated in a standardized way. The association between costs and percentage weight loss after 1 year was assessed using regression analysis.
Nineteen original studies describing 31 interventions were selected. The relationship between weight loss and intervention costs was best described by an asymptotic regression model, which explained 47% of the variance in weight loss. A clinically relevant weight loss of 5% was already observed in interventions of approximately €110. Results were similar in an intention-to-treat analysis.
In conclusion, lifestyle interventions in health care for overweight adults are relatively cheap and higher intervention costs are associated with more weight loss, although the effect of costs on weight loss levels off with growing costs.