RESUMO
OBJECTIVES: Morbid obesity represents high costs to health institutions in controlling associated comorbidities. It has been shown that bariatric surgery resolves or improves comorbidities, thus reducing resource utilization. This analysis estimated the total costs of treating morbid obesity and related comorbidities through conventional treatment compared to bariatric surgery under the Mexican public health system perspective. METHODS: An economic evaluation model was developed by using discrete event simulation. One hundred fifty patients were created in each arm, with considered comorbidities allocated randomly. Preoperative comorbidity prevalences and bariatric surgery's efficacy for resolving them were obtained from published literature. Comorbidity treatment costs were obtained from the 2007 Mexican Institute of Social Security diagnosis-related group list and publications from the National Institute of Public Health. Only 12 patients were operated each month on the surgical arm. Complications associated with comorbidities were not considered. The considered time frame for simulation was 10 years, with a 4.5% annual discount rate. RESULTS: Return on investment, or cost breakeven point, for bariatric surgery was obtained after 6.8 years. Total costs for the surgical group were 52% less than conventional treatment group costs after 10 years. Bariatric surgery reduced the cost of treating type 2 diabetes, hypertension, and hypercholesterolemia by 59%, 53%, and 65%, respectively. Return on investment for bariatric surgery in patients with type 2 diabetes as the only comorbidity was 4.4 years. CONCLUSIONS: Despite conservative assumptions, investment in bariatric surgery is recouped in 6.8 years, generating relevant potential savings in the treatment of morbidly obese patients. In high-risk subpopulations, return on investment time is shorter.
RESUMO
OBJECTIVES: To develop algorithms for a conversion of disease-specific quality-of-life into health state values for morbidly obese patients before or after bariatric surgery. METHODS: A total of 893 patients were enrolled in a prospective cross-sectional multicenter study. In addition to demographic and clinical data, health-related quality-of-life (HRQoL) data were collected using the disease-specific Moorehead-Ardelt II questionnaire (MA-II) and two generic questionnaires, the EuroQoL-5D (EQ-5D) and the Short Form-6D (SF-6D). Multiple regression models were constructed to predict EQ-5D- and SF-6D-based utility values from MA-II scores and additional demographic variables. RESULTS: The mean body mass index was 39.4, and 591 patients (66%) had already undergone surgery. The average EQ-5D and SF-6D scores were 0.830 and 0.699. The MA-IIwas correlated to both utility measures (Spearman's r = 0.677 and 0.741). Goodness-of-fit was highest (R(2) = 0.55 in the validation sample) for the following item-based transformation algorithm: utility (MA-II-based) = 0.4293 + (0.0336 x MA1) + (0.0071 x MA2) + (0.0053 x MA3) + (0.0107 x MA4) + (0.0001 x MA5). This EQ-5D-based mapping algorithm outperformed a similar SF-6D-based algorithm in terms of mean absolute percentage error (P = 0.045). CONCLUSIONS: Because the mapping algorithm estimated utilities with only minor errors, it appears to be a valid method for calculating health state values in cost-utility analyses. The algorithm will help to define the role of bariatric surgery in morbid obesity.
