Diabetes remission 10 years after bariatric surgery: Extension study of a randomized controlled trial

Metabolic bariatric surgery (MBS) is highly effective for improving glycemic control in patients with severe obesity and type 2 diabetes (T2D), yet long-term evidence remains limited. Understanding the durability of remission and the mechanisms that sustain metabolic benefits is essential for guiding surgical decision-making.

This 10-year extension study follows participants from the DIABETCIR randomized controlled trial, in which adults with severe obesity and T2D were randomized 1:1:1 to Roux-en-Y gastric bypass (RYGB) with long biliopancreatic limb, sleeve gastrectomy (SG), or greater curvature plication (GCP). Clinical, anthropometric, and biochemical data were collected at baseline, 1 year, 5 years, and up to 10 years after surgery. Fasting concentrations of PYY, ghrelin, glucagon, and area under the curve (AUC) of GLP-1, after a standard meal test were determined prior to and at months 1 and 12 after surgery. Outcomes included the identification of predictors of long-term diabetes remission including changes in incretin hormones using logistic regression, and longitudinal trajectories with mixed-effects models. In addition, weight loss (WL), glycemic control, remission and recurrence of T2D and time to remission were compared between surgeries at 10 years.

Forty-five patients were randomized and 93% completed the 10-year follow-up. RYGB achieved the greatest WL and superior metabolic control at 1, and 5 years but the differences were attenuated at 10 years. T2D remission rates decreased over time and at 10 years, remission persisted in n = 8/15 (53.3%) of RYGB patients, compared with n = 3/12 (25%) after SG and n = 4/15 (26.7%) after GCP. Higher probability of remission over time was observed after RYGB compared to SG and GCP group. A shorter duration of T2D, early increases in GLP-1 secretion and WL within the first postoperative year, were associated with long-term remission regardless of surgical technique. Although relapse rates were high across procedures (41.7-50.1%), the use of glucose-lowering medications decreased substantially in all treatment groups, especially after RYGB.

MBS provides durable improvements in T2D, with RYGB offering a sustained metabolic benefit. Less advanced T2D, greater initial weight loss, and a strong GLP-1 response are associated with long-term remission. These findings highlight complementary contributions of anatomical modification, weight loss, and enteroendocrine changes to long-term surgical success. The trial is registered (ISRCTN14104758) https://doi.org/10.1186/ISRCTN14104758.