Bariatric surgery significantly reduces progression from prediabetes to diabetes compared with the general population: 15-year single-institution data.

Background: There is a paucity of literature on the impact for bariatric surgery on the progression from prediabetes (PDM) to type II diabetes mellitus (T2DM).

Objectives: To evaluate the progression from PDM to T2DM in bariatric surgery compared with a nonsurgical cohort.

Setting: Single academic institution, Center of Bariatric Excellence.

Methods: This retrospective study of patients with morbid obesity with patients with PDM who underwent Roux-en-Y gastric bypass (RYGB) or sleeve gastrectomy (SG) between 2001 and 2022. Nonsurgical controls from a primary care cohort were directly matched by hemoglobin A1c, age, sex, and body mass index. DM was defined as a clinical diagnosis of type II diabetes or hemoglobin A1c ≥6.5%. Kaplan-Meier analysis was used to estimate time until T2DM. Cox regression was used to compare time until T2DM in RYGB versus sleeve gastrectomy and in bariatric surgery versus nonsurgical controls.

Results: A total of 1326 bariatric cases with PDM (n = 1154 RYGB, n = 172 SG) were identified. The cohort was 83% female, mean age = 45.3 years, mean body mass index 46.9 kg/m, and follow-up was 65% over 15 years. In bariatric cases, PDM progression to T2DM at 5, 10, and 15 years after surgery was 1.8%, 3.3%, and 6.7%, respectively. PDM progression to T2DM was almost 20 times greater in matched nonsurgical controls at 5, 10, and 15 years 31.1%, 51.4%, and 68.7%, respectively (hazard ratio 19.8, 95% confidence interval 13.9-28.4, P < .0001). When stratifying by bariatric surgery type, those with SG were 4 times more likely to progress to T2DM versus RYGB (hazard ratio 4.01, 95% confidence interval 1.71-9.39, P = .0014).

Conclusions: Bariatric surgery significantly decreases the conversion from PDM to T2DM. The impact was significantly greater for RYGB compared with SG.