Metabolic surgery bests medical/lifestyle management for people with diabetes in the long run

Individuals with type 2 diabetes (T2D) may fare better with metabolic bariatric surgery, which confers more favourable long-term outcomes as compared with intensive medical and lifestyle management, based on the 7- and 12-year data from the ARMMS-T2D* trial.

“Metabolic surgery improves diabetes-related outcomes more than medical/lifestyle treatment for individuals with T2D,” said one of the ARMMS-T2D investigators Dr Anita Courcoulas of the University of Pittsburgh, Pittsburgh, Pennsylvania, US, who spoke to an audience at ADA 2023.

The primary endpoint of mean A1C was 7.2 percent in the surgery group vs 8.2 percent in the medical/lifestyle arm at 7 years, and 7.3 percent vs 8.0 percent, respectively, at 12 years. Of note, a higher number of participants in the surgery arm were in diabetes remission, defined as A1C <6.5 percent without medications, at 7 years (18.2 percent vs 6.2 percent) and at 12 years (12.7 percent vs 0 percent).

Glycaemic control with an A1C <7 percent was also more likely to be achieved with metabolic surgery than with medical/lifestyle management at 7 years (54 percent vs 27 percent) and at 12 years (55 percent vs 29 percent).

Finally, participants in the surgery group lost more weight at 7 years (19.9 percent vs 8.3 percent) and at 12 years (19.3 percent vs 10.8 percent) compared with those in the medical/lifestyle group.

“These improvements followed the same pattern in the subgroup of participants who had class 1 obesity with a body mass index (BMI) <35 kg/m²,” Courcoulas pointed out.

As for safety, metabolic surgery was associated with increased risks of anaemia, fractures, and gastrointestinal symptoms.

The value of weight loss

ARMMS-T2D was a prospective, observational follow-up of four randomized controlled trials in which the effects of metabolic surgery were evaluated against that of medical and lifestyle management between 2007 and 2013: STAMPEDE, which was conducted at the Cleveland Clinic; SLIMM-T2D at Brigham and Women’s Hospital and Joslin Diabetes Center; TRIABETES at the University of Pittsburgh; and CROSSROADS at the University of Washington.

The parent trials included a total of 355 participants with T2D who were randomly assigned to (1) receive intensive medical and weight management for at least a year plus continuing care with currently available medications and lifestyle support or (2) undergo metabolic bariatric surgery. Of the original parent trial participants, 186 from the metabolic surgical arm and 96 from the medical/lifestyle arm were enrolled in ARMMS-T2D. All participants were followed for at least 7 years.

“Before ARMMS-T2D, we knew that bariatric surgery is the most effective and durable intervention for weight loss in class 3 obesity, but the obesity trials were not randomized and were not reflective of the populations we see in diabetes clinic,” said one of the original ARMMS-T2D collaborators at Cleveland Clinic Dr Sangeeta Kashyap of Weill Cornell Medical Center, New York City, New York, US.

“About 40 percent of ARMMS-T2D participants had class 1 obesity with a BMI <35 kg/m². The parent trials all showed greater glycaemic control and diabetes remission with surgery, but they were relatively short term. The clinical challenge has always been to maintain weight loss for longer-term clinical benefit,” Kashyap said.

In light of the long-term results of ARMMS-T2D, Courcoulas stated, “Clinicians should consider metabolic surgery as an option to improve diabetes-related outcomes, including for people with BMI <35 kg/m².”

Extension of benefit to NAFLD

In a separate analysis of the long-term ARMMS-T2D data, metabolic surgery also proved superior to medical/lifestyle management for improving hepatic steatosis scores in participants with T2D.

Steatosis and fibrosis rates at baseline did not differ between the surgery and medical/lifestyle arms. However, at the latest follow-up, patients who underwent metabolic surgery had significantly greater decrease in weight (–20.1 vs –11.2 kg; p<0.001) and HbA1c (–1.10 percent vs –0.50 percent; p<0.001), as well as higher incidence of diabetes remission (16.8 percent vs 2.2 percent; p<0.001). [ADA 2023, abstract 372-OR]

Furthermore, steatosis scores improved to a greater extent in the surgery arm (–8.5 vs –4.9; p<0.001). On the other hand, fibrosis scores remained relatively unchanged in the surgical and medical/lifestyle arms (FIB-4 –0.01 vs –0.02; p=0.77; APRI –0.04 vs –0.01; p=0.60).

“Fibrosis scores did not worsen as would be expected with ageing, suggesting a protective effect of both surgical and medical interventions. These results support a continued role for weight loss interventions to prevent and treat nonalcoholic fatty liver disease (NAFLD),” according to the investigators.

*Alliance of Randomized Trials of Medical Management vs. Metabolic Surgery for Type 2 Diabetes