Association Between Bariatric Surgery and Macrovascular Disease Outcomes in Patients With Type 2 Diabetes and Severe Obesity
JAMA. 2018;320(15):1570-1582; Fisher D, Johnson E, Haneuse S et al.

Heart attacks occur because of the sudden obstruction of the blood flow in the coronary arteries. A blood clot causes the obstruction on the background of a ruptured atherosclerotic plaque in the coronary artery wall. It has been known for a long time that obesity is associated with high cholesterol, diabetes and high blood pressure, which lead to coronary artery disease and heart attack. There is also a direct link between obesity and heart attack, and therefore obesity itself is an independent cardiovascular risk factor. Even a modest weight loss results in decreased cardiovascular risk. If you are overweight, losing only a few pounds will significantly reduce your risk of a heart attack. Many patients with severe obesity are however not able to reduce weight with diet and exercise alone. Drug treatment of obesity yielded generally disappointing results with many safety concerns.

The study published last month in the Journal of the American Medical Association adds to the growing body of evidence regarding the beneficial effect of bariatric surgery in patients with severe obesity (BMI 35 and more) and type 2 diabetes mellitus. 

The authors conducted a retrospective matched cohort study involving 5,301 patients with severe obesity and diabetes who underwent bariatric surgery (76% Roux-en-Y gastric bypass, 17% sleeve gastrectomy, and 7% adjustable gastric banding) and were matched to control non-surgical patients. 

Bariatric procedures in these patients were associated with a lower risk for macrovascular outcomes compared with not undergoing surgery. The researchers identified 106 macrovascular events in surgical patients over a median of 4.7 years and 596 events in matched control patients over a median of 4.6 years. At five years, bariatric surgery correlated with a lower composite incidence of macrovascular events (2.1% versus 4.3%; hazard ratio, 0.60 [95% CI, 0.42-0.86] and lower incidence of coronary artery disease (1.6% versus 2.8%; hazard ratio, 0.64 [95% CI, 0.42-0.99]).

These are impressive results, but it is worth noting that this was an observational study that requires confirmation in randomised clinical trials. Health care professionals should engage patients with severe obesity and type 2 diabetes in a shared decision making conversation about the potential role of bariatric surgery in preventing macrovascular events.