Impact of metabolic and bariatric surgery on weight loss and insulin requirements in type 1 and insulin-treated type 2 diabetes

Metabolic and Bariatric Surgery (MBS) is effective in improving metabolic outcomes and reducing weight in patients with obesity and diabetes, with less explored benefits in type 1 diabetes (T1D). This study aimed to evaluate the impact of MBS on weight loss and insulin requirements in T1D patients compared to insulin-treated type 2 diabetes (T2D) patients over a 5-year period. This retrospective analysis included patients who underwent primary sleeve gastrectomy (SG) or Roux-en-Y gastric bypass (RYGB) with a confirmed preoperative diagnosis of either T1D or insulin-treated T2D. Primary endpoints focusing on weight loss and secondary outcomes assessing changes in insulin dosage and glycemic control. After 5 years, weight loss was similar across groups, with total weight loss at 14.2% for T1D and 17.6% for insulin-treated T2D in SG, and 22.6% for T1D vs. 26.8% for insulin-treated T2D in RYGB. Additionally, there was a significant reduction in median daily insulin doses from 140.5 units at baseline to 77.5 units at 1 year postoperatively, sustained at 90 units at 5 years. The differential impact of MBS procedure was also highlighted, where RYGB patients showed a more pronounced and enduring decrease in insulin requirements compared to SG.