A study of nearly 20,000 patients with type 2 diabetes and severe obesity found that bariatric surgery significantly lowered the risk of macrovascular events at 5 years. Clinicians should engage patients with obesity and diabetes in shared-decision making conversations about this course of treatment.


 

Macrovascular disease, which includes coronary artery disease and cerebrovascular disease, is one of the leading causes of morbidity and mortality for patients with type 2 diabetes. Guidelines for the management of type 2 diabetes emphasize lowering macrovascular disease risk factors by optimizing glycemic control, blood pressure, and serum lipid levels. Despite these recommendations, most patients with the disease do not achieve these treatment goals, resulting in continued morbidity and costs.

“Bariatric surgery is the most effective way for adults with severely obesity to lose weight, and patients with diabetes experience rapid and durable improvements in glycemic control after these operations,” says David Arterburn, MD, MPH. “However, it’s unknown if improvements in weight and glycemic control after bariatric surgery also translate into a lower risk of major macrovascular events among people with severe obesity and type 2 diabetes. Previous observational studies have sought to address this question but were limited by low numbers of participants who received current bariatric procedures or a lack of a rigorously defined control groups.”

 

Important New Data

In a retrospective study published in JAMA, Dr. Arterburn and colleagues matched more than 5,000 patients with severe obesity and diabetes who underwent bariatric surgery from 2005 to 2011 at one of four health systems in the United States with nearly 15,000 non-surgical control patients. Electronic medical records provided data for matching surgical patients to controls using age, sex, BMI, A1C, insulin use, diabetes duration, and prior healthcare utilization.

In total, the average age of the study population was 50 years, and three-quarters of patients assessed in the analysis were women. Roux-en-Y gastric bypass was the most common bariatric surgery, but others received sleeve gastrectomy or adjustable gastric banding. Macrovascular events were defined as a composite of coronary artery disease, including acute myocardial infarction, unstable angina, PCI, and CABG surgery, and cerebrovascular disease, which included ischemic stroke, hemorrhagic stroke, carotid stenting, or carotid endarterectomy.

The study estimated the cumulative probability of incident macrovascular disease over time after bariatric surgery and usual non-surgical care (Table). “A key finding was that bariatric surgery was associated with a 40% lower incidence of major macrovascular events at 5 years when compared with the non-surgical medical care,” says Dr. Arterburn. “Bariatric surgery recipients also had a lower incidence of coronary heart disease, but the incidence of cerebrovascular disease was not significantly lower. Another critical finding was that bariatric surgery was associated with a 66% lower risk of dying from any cause at 5 years when compared with usual medical care.”

 

Significant Implications

According to Dr. Arterburn, future research will determine if patients with earlier-stage diabetes will benefit more from bariatric surgery in terms of macrovascular events and cost-effectiveness. “In the meantime,” he says, “our study provides longitudinal follow-up data suggesting that bariatric surgery may significantly reduce the risk of heart attack and stroke among patients with severe obesity and type 2 diabetes when compared with usual medical care. As such, clinicians should discuss bariatric surgery as a treatment option when managing patients who have type 2 diabetes and severe obesity. Although some patients may not be interested in bariatric surgery, they should at least be made aware of the evidence.”

Despite existing evidence supporting the inclusion of bariatric surgery as an intervention to treat type 2 diabetes and obesity, surgical options are still not included in many existing diabetes treatment algorithms. This may be due to several reasons, such as limited access to bariatric surgery because of stringent private insurance requirements, lack of Medicaid coverage in some states, and high out-of-pocket costs. “To overcome potential barriers to bariatric surgery, it’s critical that healthcare providers engage patients in shared decision-making conversations about their treatment options,” says Dr. Arterburn. “Bariatric surgery should be discussed with every patient who has severe obesity and type 2 diabetes and doesn’t have a clear contraindication to the procedure.”

References

Fisher DP, Johnson E, Haneuse S, et al. Association between bariatric surgery and macrovascular disease outcomes in patients with type 2 diabetes and severe obesity. JAMA. 2018;320:1570-1582. Available at: https://jamanetwork.com/journals/jama/fullarticle/2707461.

Adams TD, Arterburn DE, Nathan DM, Eckel RH. Clinical outcomes of metabolic surgery: microvascular and macrovascular complications. Diabetes Care. 2016;39:912-923.

Low Wang CC, Hess CN, Hiatt WR, Goldfine AB. Clinical update: cardiovascular disease in diabetes mellitus: atherosclerotic cardiovascular disease and heart failure in type 2 diabetes mellitus: mechanisms, management, and clinical considerations. Circulation. 2016;133:2459-2502.

Arterburn DE, O’Connor PJ. A look ahead at the future of diabetes prevention and treatment. JAMA. 2012;308:2517-2518.