Purpose: Obesity is associated with increased morbidity and mortality. Weight loss due to gastric bypass (GBP) surgery improves clinical outcomes and may be a cost-effective intervention. To estimate the cost-effectiveness of GBP compared to clinical treatment in severely obese individuals with and without diabetes in the perspective of the Brazilian public health system.
Materials and methods: A Markov model was developed to compare costs and outcomes of gastric bypass in an open approach to clinical treatment. Health states were living with diabetes, remission of diabetes, non-fatal and fatal myocardial infarction, and death. We also included the occurrence of complications related to surgery and plastic surgery after the gastric bypass surgery. The direct costs were obtained from primary data collection performed in three public reference centers for obesity treatment. Utility values also derived from this cohort, while transition probabilities came from the international literature. A sensitivity analysis was performed to evaluate uncertainties. The model considered a 10-year time horizon and a 5% discount rate.
Results: Over 10 years, GBP increased quality-adjusted life years (QALY) and costs compared to clinical treatment, resulting in an incremental cost-effectiveness ratio (ICER) of Int$1820.17/QALY and Int$1937.73/QALY in individuals with and without diabetes, respectively. Sensitivity analysis showed that utility values and direct costs of treatments were the parameters that affected the most the ICERs.
Conclusion: The study demonstrated that GBP is a cost-effective intervention for severely obese individuals in the Brazilian public health system perspective, with a better result in individuals with diabetes.
Keywords: Cost-utility; Gastric bypass surgery; Obesity.