Bariatric Surgery Outperforms Drugs, Lifestyle Interventions in Reversing Diabetes in Study

The randmized controlled trial confirms findings in observational studies that gastric bypass provides benefits beyond weight loss, and suggests BMI should not be the only consideration for who should have surgery. The fact that the study is associated with a major US payer is noteworthy.

Having bariatric surgery—a procedure once reserved for the severely obese—is more effective than diet and exercise regimens and anti-diabetic drugs in reversing type 2 diabetes among those with mild obesity, a new study has found.

The study, published in the current issue of Diabetologia, reports findings from David E. Cummings, MD, of the University of Washington, Seattle, and colleagues at Group Health Research Institute, the research arm of the major health insurer. The results add to those of earlier studies that suggest looking only at body mass index (BMI) to qualify patients for surgery fails to take other benefits into account.

Evidence is showing that the Roux-en-Y gastric bypass (RYGB) procedure can not only reverse T2D, but it can also produce cardiovascular benefits, such as reduced risk of heart attack and stroke, as well as reduced risk of cancer. Authors report that observational studies have found the procedure is associated with a 92% reduction in diabetes-related deaths.

In the current study, the authors compared the RYGB procedure to an intensive lifestyle intervention for T2D among patients with mild obesity, meaning they all had less than 35 BMI (the CDC definition of obesity is 30 BMI).

Researchers screened 1808 adults who met the criteria. Only 43 agreed to be randomly assigned to surgery or non-surgery. The lifestyle intervention involved 45 minutes or more of aerobic exercise 5 days a week, a dietitian supervised glucose lowering diet, and optimal therapy for a year. The primary outcome was whether patients achieved glycated hemoglobin (A1C) of <6.0% without medication after a year.

Twenty-three volunteers had the surgery and 20 had the lifestyle intervention. Of these, 11 withdrew, leaving 15 in the surgery group and 17 in the lifestyle intervention group. Most characteristics were equivalent except the surgery group had lived longer with diabetes—an average of 11.4 years compared with 6.8 years.

At the end of 1 year, weight loss for the surgery group was 25.8%, compared with 6.4% for the lifestyle intervention group. The intervention group had a 22% increase in exercise capacity, while capacity for the surgery group was unchanged. Diabetes remission for the surgery group at 1 year was 60%, while it was 6% for the intervention group. Average decline in A1C at 1 year was 7.7% to 6.4% for the surgery group, compared with 7.3% to 6.9% for the lifestyle intervention group. However, the surgery group took far fewer or no medications.

No life-threatening complications occurred in either group.

“These findings call into serious question the longstanding practice of using strict BMI cut-offs as the primary criteria for selection for bariatric surgery among patients with type 2 diabetes,” the authors wrote.

Reference

Cummings DE, Arterburn DE, Westbrook EO, et al. Gastric bypass surgery vs intensive lifestyle and medical intervention for type 2 diabetes: the CROSSROADS randomized controlled trial [published online March 17, 2016]. Diabetologia. 2016; 10.1007/s00125-016-3903-x.