Does bariatric surgery reduce the risk of major cardiovascular events? A retrospective cohort study of morbidly obese surgical patients.

BACKGROUND: Morbid obesity is associated with the development of cardiovascular and cerebrovascular disease. Several studies have shown that bariatric surgery results in risk factor reduction; however, studies correlating bariatric surgery to the reduced rates of myocardial infarction, stroke, or death have been limited.
METHODS: We conducted a large retrospective cohort study of bariatric (BAR) surgical patients (n = 4747) and morbidly obese orthopedic (n = 3066) and gastrointestinal (n = 1327) surgical controls. Data were obtained for all patients aged 40-79 years, from 1996 to 2008, with a diagnosis code of morbid obesity and a primary surgical procedure of interest. The data sources were the statewide South Carolina Universal Billing Code of 1992 inpatient hospitalization database and death records. The primary study outcome was the time-to-occurrence of the composite outcome of postoperative myocardial infarction, stroke, or death (all-cause).
RESULTS: The 5-year Kaplan-Meier life table estimate of the composite index of event-free survival in the BAR, orthopedic, and gastrointestinal cohorts was 84.8%, 72.8%, and 65.8%, respectively. After adjusting for baseline differences and potential confounders, the Cox proportional hazards ratio was .72 (95% confidence interval .58-.89) for BAR versus orthopedic and .48 (95% confidence interval .39-.61) for BAR versus gastrointestinal.
CONCLUSION: Bariatric surgery was significantly associated with a 25-50% risk reduction in the composite index of postoperative myocardial infarction, stroke, or death compared with other morbidly obese surgical patients in South Carolina.