OBJECTIVES: It was performed a cost-effectiveness study with a systematic review and meta analysis of the bariatric surgery for treatment of moderate to severe obesity and obesity-related diseases and the costs before and after the bariatric surgery.

METHODS: Systematic review and meta-analysis of studies on costs and effectiveness of the bariatric surgery focusing on outcomes of chronic noncommunicable diseases associated with overweight and obesity and the expenditures in the treatment before and after the bariatric surgery

RESULTS: It was fully reviewed 51 studies with costs and effectiveness of bariatric surgery. The majority of studies pointed to reduction in direct costs related to comorbidities after bariatric surgery. The average cost of bariatric surgery was US$ 49,419.63(±96,707.49; median=12,661.96 and quartiles of 5,414.5-33,679.10). The average cost of treatment for comorbidities among patients without surgery was US$40,342.30 (±37,716.16; median=31,958.46 and quartiles of 4,871.03-69,200.00). The results of the total effectiveness shown wide benefits of the bariatric surgery in all evaluated items (RR 0.571 CI95% 0.482–0.660, p<0,001), including the reduction in total expenditure (RR 0.652 CI95% 0.465–0.841, p<0,001), reduction of needs of medicines (RR 0.160 CI95% 0.005–0.314, p<0,001), decrease of relative risk of hypertension (RR 0.589 CI95% 0.493–0.685, p<0,001), decrease of relative risk of diabetes (RR 0.400 CI95% 0.609–0.741, p<0,001), cardiovascular diseases (RR 0.578 CI95% 0.349–0.807, p<0,001), dyslipidemia (RR 0.721 CI95% 0.562–0.881, p<0,001), obesity-related mortality (RR 0.505 CI95% 0.345–0.665, p<0,001), obesity-related cancer (RR 0.675 CI95% 0.609–0.741, p<0,001) and depression (RR 0.829 CI95% 0.794–0.865, p<0,001), compared to conservative or non-surgical treatment.

CONCLUSIONS: The bariatric surgery is cost-saving and cost-effective in reducing obesity-related diseases. The results shown that bariatric surgery is able to reduce the costs and the risk of the main chronic obesity-related diseases in short, mediun and long term, also decreasing the risk of mortality and depression, in comparison of traditional treatment for the obese person.