SAN DIEGO — Bariatric surgery produced sustained, long-term glucose control and weight loss for at least 7 years, and for up to 12 years, in some US 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 American Diabetes Association 83rd Scientific Sessions.
People who underwent bariatric surgery (gastric band, sleeve gastrectomy, or Roux-en-Y gastric bypass) had an average 1.6-percentage point drop in 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 timepoints, 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 Courcoulas, a professor of surgery at the University of Pittsburgh, Pennsylvania.
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).
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 UStrials that all began more than a decade ago, prior to 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 Eckel, an endocrinologist and emeritus professor at the University of Colorado School of Medicine in Aurora.
ARMMS-T2D included data from 262 people with overweight or obesity and type 2 diabetes randomized in any of four US 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
A Quartet of Studies Joined Together
The ARMMS-T2D prospective analysis resulted from an early partnership by the organizers of the four independent randomized studies that compared bariatric surgery with lifestyle and medical intervention in people with type 2 diabetes and overweight or obesity: STAMPEDE, which included 150 people at the Cleveland Clinic starting in 2007; SLIMM-T2D, which included 88 people at Brigham and Women's Hospital and the Joslin Diabetes Center in Boston starting in 2010; TRIABETES, which included 69 people at the University of Pittsburgh starting in 2009; and CROSSRAODS, which included 43 people at the University of Washington in Seattle starting in 2011.
Further secondary findings from the ARMMS-T2D analyses showed that 38% of the surgery patients and 17% of controls had an A1c < 6.5% after 7 years.
At 7 years, type 2 diabetes remission, defined as those with an A1c < 6.5% who were not taking any antidiabetes medications, was reached in 18% of surgery patients and 6% of controls. At 12 years, 13% of the surgery patients and none of the controls met this metric, Courcoulas said.
The duration of diabetes a person had before undergoing bariatric surgery "may be an important factor" as to whether patients undergo remission, suggested Eckel. He noted that longer duration type 2 diabetes usually results in increased glucose intolerance and makes remission less likely
Roux-en-Y gastric bypass appeared to have the best rates of patients achieving both lower A1c levels and more weight loss, followed by sleeve gastrectomy and gastric banding, which had the worst performance. But Courcoulas cautioned that the study was underpowered to reliably compare individual surgical procedures.
In terms of those with an A1c < 7.0%, surgery patients maintained a steady prevalence rate of about 55% during the first 5 years of follow-up, roughly twice the rate of controls, at 28% during all years of follow-up starting at year 5.
About 37% of enrolled patients had a BMI < 35 kg/m2, and the A1c-lowering benefit and weight loss in this subgroup were consistent with the overall findings, which supports consideration of bariatric surgery for people with type 2 diabetes and a BMI < 35 kg/m2, Courcoulas said.
She also highlighted that bariatric surgery was linked with significant reductions in triglyceride levels and increased high-density lipoprotein cholesterol levels, compared with controls. However, 22% of surgery patients experienced abdominal pain compared with 10% of controls, and 7% experienced dysphagia compared with no cases among the controls.
ARMMS-T2D received no commercial funding. Courcoulas had no disclosures. Eckel has been a consultant to numerous companies but said he had no relevant disclosures.
ADA Scientific Sessions. Session CT-1-SY34. Presented June 26, 2023.
Mitchel L. Zoler is a reporter for Medscape and MDedge based in the Philadelphia area. @mitchelzoler
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Cite this: Benefits of Bariatric Surgery Persist for 12 Years - Medscape - Jul 28, 2023.