Bariatric surgery is a cost-saving treatment for obesity – a comprehensive meta-analysis and updated systematic review of health economic evaluations of bariatric surgery

Demand for bariatric surgery to treat severe and resistant obesity far outstrips supply. We aimed to comprehensively synthesise health economic evidence regarding bariatric surgery from 1995 to 2018 (PROSPERO registration number: CRD42018094189). Meta-analyses were conducted to calculate the annual cost changes "before" and "after" surgery, and cumulative cost differences between surgical and nonsurgical groups. An updated narrative review also summarized the full and partial health economic evaluations of surgery from September 2015. N = 101 studies were eligible for the qualitative analyses since 1995, with n = 24 studies after September 2015. Quality of reporting has increased, and the inclusion of complications/reoperations was predominantly contained in the full economic evaluations after September 2015. Technical improvements in surgery were also reflected across the studies. Sixty-one studies were eligible for the quantitative meta-analyses. Compared with no/conventional treatment, surgery was cost saving over a lifetime scenario. Additionally, consideration of indirect costs through sensitivity analyses increased cost savings. Medication cost savings were dominant in the before versus after meta-analysis. Overall, bariatric surgery is cost saving over the life course even without considering indirect costs. Health economists are hearing the call to present higher quality studies and include the costs of complications/reoperations; however, indirect costs and body contouring surgery are still not appropriately considered.