Effect of gastric bypass operation on Framingham and actual risk of cardiovascular events in class II to III obesity

BACKGROUND: Obesity is known to be a major risk factor for cardiovascular diseases. There are few studies in the literature assessing the effect of bariatric procedures on longterm risk of cardiovascular events. The aim of this study was to determine the effect of gastric bypass operation on actual and Framingham risk of coronary heart disease (CHD) events in class II to III obesity. STUDY DESIGN: In a cohort of subjects with class II to III obesity, we used the observed change in CHD risk factors and risk models derived from the Framingham data equation to calculate the predicted 10-year absolute and relative risk of CHD after gastric bypass operation. The risk predicted by the Framingham model was then compared with the actual incidence of CHD events of the cohort. RESULTS: Five-hundred patients were included in the study. The 1-year mean excess body weight loss was 68.7% +/- 22%. There was a substantial reduction in prevalence of diabetes from 28% to 6% (p = 0.001). Compared with baseline, the average 10-year absolute risk of cardiac events decreased from 5.4% at baseline to 2.7% at 1 year after operation (p = 0.001). A similar risk reduction was observed in subgroups defined by diabetes status and gender. Gastric bypass decreased absolute risk of cardiac events by a mean of 63% (p = 0.0001) in diabetics and 56% (p = 0.001) in male patients. The cohort actual rate of CHD events was 1% (5 of 500). At the 5-year horizon, this was considerably (p = 0.001) lower than the predicted rate before gastric bypass operation. CONCLUSIONS: Gastric bypass operation is effective in reducing actual and the 10-year Framingham risk of CHD events in individuals with class II to III obesity. The major estimated risk reduction was observed in male patients with type 2 diabetes.