Bariatric Surgery and Long-Term Cardiovascular Events
Does bariatric surgery, resulting in weight loss, reduce the risk of cardiovascular (CV) events?
Data from the Swedish Obese Subjects (SOS) study were used for the current analysis. The SOS study is an ongoing nonrandomized prospective study, which included 2,010 obese subjects who underwent bariatric surgery and 2,037 contemporaneously matched obese controls who received usual care, recruited between September 1, 1987, and January 31, 2001. Inclusion criteria were ages 37-60 years and a body mass index (BMI) of at least 34 in men and at least 38 in women. Exclusion criteria were identical in surgery and control patients. The primary outcomes of interest included myocardial infarction and stroke.
At baseline, the mean BMI was 40.1 in the control group and 42.4 in the surgery group. The mean changes in body weight after 2, 10, 15, and 20 years were −23%, −17%, −16%, and −18% in the surgery group and 0%, 1%, −1%, and −1% in the control group. Surgery patients underwent gastric bypass (13.2%), banding (18.7%), or vertical banded gastroplasty (68.1%), and controls received usual care in the Swedish primary health care system. Over a median follow-up of 14.7 years, bariatric surgery was associated with a reduced number of CV deaths (28 events in the surgery group vs. 49 events in the control group; adjusted hazard ratio [HR], 0.47; 95% confidence interval [CI], 0.29-0.76; p = 0.002). The number of total first time (fatal or nonfatal) CV events (myocardial infarction or stroke, whichever came first) was lower in the surgery group (199 events in the surgery group vs. 234 events for the control group; adjusted HR, 0.67; 95% CI, 0.54-0.83; p < 0.001). Higher baseline insulin concentrations were associated with more favorable outcomes in bariatric surgery patients. No significant interactions were noted between BMI, or other metabolic and anthropometric variables, bariatric surgery, and CV outcomes.
The authors concluded that compared with usual care, bariatric surgery was associated with a reduced number of CV deaths and lower incidence of CV events in obese adults.
This study provides evidence that bariatric surgery resulting in weight loss also lowers risk for CV outcomes, although the study is limited by the lack of randomization. Further research is need to fully understand which patients benefit the most from such surgeries, and what is key to CV risk modification.
Keywords: Myocardial Infarction, Stroke, Bariatric Surgery, Follow-Up Studies, Body Mass Index, Gastric Bypass, Weight Loss, Gastroplasty, Obesity
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