Conference Coverage

Benefits of bariatric surgery persist for 12 years


AT ADA 2023

Bariatric surgery produced sustained, long-term glucose control and weight loss for at least 7 years, and for up to 12 years, in some U.S. patients with type 2 diabetes and a baseline body mass index (BMI) of at least 27 kg/m2, according to new study results.

The findings are from ARMMS-T2D, a prospective, controlled trial with the largest cohort and longest follow-up of bariatric surgery reported to date. The results reinforce the potential role of surgery “as an option to improve diabetes-related outcomes, including people with a BMI of less than 35 kg/m2,” said Anita P. Courcoulas, MD, at the recent annual scientific sessions of the American Diabetes Association.

People who underwent bariatric surgery (gastric band, sleeve gastrectomy, or Roux-en-Y gastric bypass) had an average 1.6–percentage point drop in hemoglobin A1c from baseline 7 years after surgery and an average 1.4–percentage point reduction from baseline after 12 years. Average decreases from baseline were 0.2 and 0.3 percentage points at these time points, respectively, among controls who underwent lifestyle and medical interventions only. Between-group differences were significant at both the 7-year (primary endpoint) and 12-year time points in the intention-to-treat analysis, reported Dr. Courcoulas, a professor of surgery at the University of Pittsburgh.

Average weight loss from baseline to 7 and 12 years was 19.9% and 19.3%, respectively, in the surgery group and 8.3% and 10.8%, respectively, among controls, which was significantly different between groups at both time points (a secondary endpoint).

Dr. Courcoulas highlighted that the 10.8% average weight loss after 12 years among controls included crossovers, with 25% of patients progressing from their initial intervention of lifestyle and medical management to undergoing bariatric surgery during follow-up. Among the controls who never underwent surgery (per-protocol analysis), the 12-year average weight loss from baseline was 7.3%.

High-dose incretin-hormone therapy missing

A major limitation of ARMMS-T2D (Alliance of Randomized Trials of Medicine vs. Metabolic Surgery in Type 2 Diabetes) is that it prospectively followed a combined cohort from four independently run controlled U.S. trials that all began more than a decade ago, before the contemporary era of medical weight loss management that’s been revolutionized by incretin-hormone receptor agonists such as semaglutide (Ozempic/Wegovy, Novo Nordisk) and tirzepatide (Mounjaro, Lilly).

New randomized, controlled trials “are needed” that compare metabolic bariatric surgery with medical and lifestyle management that includes “high-dose incretin-hormone therapy,” commented Robert H. Eckel, MD, designated discussant for ARMMS-T2D at the session.

The results also showed notable rates of two adverse events associated with bariatric surgery: a 14% incidence of bone fractures, compared with a rate of 5% among controls, and a 12% incidence of anemia after surgery, compared with a rate of 3% among controls.

The control group also had a significantly higher 3% incidence of new need for hemodialysis, compared with no incident dialysis cases among the surgery patients.

“The fracture difference [after bariatric surgery] needs more careful follow-up,” commented Dr. Eckel, an endocrinologist and emeritus professor at the University of Colorado at Denver, Aurora.

ARMMS-T2D included data from 262 people with overweight or obesity and type 2 diabetes randomized in any of four U.S. studies that compared the outcomes of 166 patients who underwent bariatric surgery with 96 patients who served as controls and had lifestyle and medical interventions for weight loss and glycemic control. Seven-year follow-up included 82 (85%) of the initial 96 control patients and 136 (82%) of the initial 166 surgery patients. After 12 years, 31 of the controls (32%) and 83 surgery patients (50%) remained for the A1c analysis.


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