Risk of Myocardial Infarction, Ischemic Stroke, and Mortality in Patients Who Undergo Gastric Bypass for Obesity Compared With Nonoperated Obese Patients and Population Controls.

OBJECTIVE: The aim of this study was to estimate risks of myocardial infarction, ischemic stroke, and cardiovascular-related and all-cause mortality after Roux-en-Y gastric bypass (RYGB) for obesity compared with nonop-erated obese patients and matched nonobese population controls. BACKGROUND: Few studies have assessed the influence of RYGB on fatal and non-fatal myocardial infarction and ischemic stroke, and the results vary between studies. METHOD: All patients aged 20 to 65 years with obesity diagnosis in the nationwide Swedish Patient Registry in 2001 to 2013 were included. These participants were divided into those who underwent RYGB within 2 years of obesity diagnosis (n = 28,204) and nonoperated (n = 40,827), and were matched for age, sex, and region with 2 nonobese population controls. Participants were followed until onset of outcome disease, death, or end of follow-up. Multivariable Cox regression provided hazard ratios (HR) with 95% confidence intervals (95% CI). RESULTS: Compared with nonoperated patients with obesity, RYGB patients had a reduced risk of myocardial infarction [HR = 0.44 (95% CI 0.28-0.63)], similar risk of ischemic stroke [HR = 0.79 (95% CI 0.54-1.14)], and decreased risks of cardiovascular-related [HR = 0.47 (95% CI 0.35-0.65)] and all-cause mortality [HR = 0.66 (95% CI 0.54-0.81)] within the first 3 years of follow-up, but not later. Compared with nonobese population controls, RYGB patients had excess risks of ischemic stroke [HR = 1.57 (95% CI 1.08-2.29)], cardiovascular-related mortality [HR = 1.82 (95% CI 1.29-2.60)], and all-cause mortality [HR = 1.42 (95% CI 1.16-1.74)], but not of myocardial infarction [HR = 1.02 (95% CI 0.72-1.46)]. CONCLUSION: RYGB for obesity might not decrease the risk of ischemic stroke, but seems to decrease the risk of myocardial infarction back to population levels.