Bariatric surgery improved HbA1c at 5 y more than intensive medical care alone in obese patients with T2DM

A commentary considers the industry-funded STAMPEDE trial, in which obese patients with type 2 diabetes were randomly assigned to intensive medical therapy alone or intensive medical therapy plus Roux-en-Y gastric bypass or sleeve gastrectomy.

In the industry-funded STAMPEDE trial, 150 patients with type 2 diabetes and a body mass index of 27 to 43 kg/m2 were randomly assigned to receive intensive medical therapy alone or intensive medical therapy plus Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy. At five-year follow-up, 5% of the medical therapy group had an HbA1c of 6% or lower, compared to 29% of those receiving RYGB and 23% of those undergoing sleeve gastrectomy.

The study was published in the Feb. 16 New England Journal of Medicine. The following commentary by Clare J. Lee, MD, MHS, and Lawrence J. Cheskin, MD, FACP, was published in the ACP Journal Club section of the May 16 Annals of Internal Medicine.

Although bariatric surgery is highly effective for treating type 2 diabetes, uncertainty about the sustainability of diabetes remission remains. For instance, the observational Swedish Obese Subjects Study showed an impressive initial diabetes remission rate with bariatric surgery (72%), but it dropped to 30% at 15 years. A recent randomized controlled trial (RCT) found a diabetes remission rate of 17% 3 years after RYGB, which is much lower than earlier observational studies. The 5-year outcomes of the STAMPEDE trial confirm, with the rigor of an RCT design, that long-term remission of diabetes can sometimes be achieved with bariatric surgery.

Comparison of diabetes remission rates across these studies is challenging due to a lack of uniform definitions of “remission” and populations with different severity and duration of diabetes. Nonetheless, the STAMPEDE trial provides high-quality evidence for the long-term effectiveness of bariatric surgery in ameliorating diabetes in patients with poorly controlled (mean HbA1c >9% at baseline) and advanced (44% insulin users) diabetes. Remission seems comparable between RYGB and sleeve gastrectomy groups, though RYGB patients required much less glucose-lowering medication at year 5.

The need for longer follow-up and larger studies—to compare the efficacy and safety profile of RYGB with sleeve gastrectomy—remains. Substantial weight loss achieved through medical management, although far less successful than bariatric surgery, also yields improvement and remission of diabetes.