Cost-effectiveness of community-based obesity prevention interventions in Australia

Objectives: To examine, from a societal perspective, the cost-effectiveness of community based interventions (CBI) - defined as a program of community-level strategies to promote healthy eating and physical activity for Australian children aged 5-18 years. Methods: The effectiveness of CBI, measured by mean difference in body mass index (BMI) z-scores, was determined by undertaking a systematic review and subsequent meta-analysis of ten quasi-experimental trials conducted between 1990 and 2016 using a random effects model. Based on the literature, a generic CBI comprised of three school-based physical activity and four nutrition components, plus wider community actions, was costed. Several programs were costed to estimate the average cost of generic program components (2010 Australian dollars). A multiple cohort Markov model that simulates diseases associated with overweight and obesity was used to estimate the long term health benefits and associated cost offsets. Outcomes were measured as BMI units saved and Health-Adjusted Life Years (HALYs) averted over the lifetime of the target population. Monte-Carlo simulation was used to estimate the Incremental Cost-Effectiveness Ratios (ICER) with 95% uncertainty intervals (UI). Scenario analyses tested variations in program intensity, target populations and intervention effect decay. Results: The estimated net costs of implementing CBI across all Local Government Areas in Australia was $550M ($220M; $866M) (intervention costs $1.00B ($0.94B; $1.06B), cost offsets $453M ($781M; -$148M)) over 3 years. This resulted in savings of 51,863 HALYs over the lifetime of the cohort. The median ICER was $15,476 per HALY saved ($2,491; $49,016), with a 98% probability of being cost-effective at a willingness to pay threshold of $50,000 per HALY. Conclusion: CBI remained cost-effective under most scenarios tested. This evaluation is part of a priority setting study of obesity prevention interventions. The relative cost-effectiveness of CBI can be assessed against other strategies when they become available.