Midterm Effects of Bariatric Surgery in Patients with Insulin-treated Type 2 Diabetes

Objective: To assess the extent and durability of the glucose-lowering effect of bariatric surgery (BS) in patients with insulin-treated type 2 diabetes mellitus (T2D).

Background: Even though BS in patients with insulin-treated T2D is likely to increase, data on the midterm effect of Roux-en-Y gastric bypass and sleeve gastrectomy in this group of patients are scant.

Setting: University hospital.

Methods: Prospective observational study (4.9±1.9 yr) on T2D outcomes, changes in hemoglobin A1C (HbA1C), and diabetes therapy in individuals with insulin-treated T2D undergoing Roux-en-Y gastric bypass (n = 24) or sleeve gastrectomy (n = 50).

Results: Diabetes remission was initially observed in 20 of 74 individuals, but relapse occurred in 13 of the 20 (65.0%) patients. Overall, marked initial reduction of HbA1C and high rates of insulin cessation were observed (HbA1C nadir 5.9%±0.9%, insulin cessation rate 66.2%). However, these were followed by progressive deterioration of HbA1C (HbA1C at last follow-up 7.4%±1.3%; P<.001) and need for insulin therapy reintroduction (rate of insulin cessation at last follow-up visit 54%; P = .04). In multivariate analysis, larger maximum percent excess weight loss and nonbasal bolus insulin therapy were identified as significant predictors of diabetes remission, insulin cessation, and durability of HbA1C<7%.

Conclusion: In insulin-treated patients with T2DM, BS is associated with a low likelihood of midterm diabetes remission. Overall, in this group of patients, the marked initial improvement of glycemic control and insulin independence are of limited durability. In addition, in this group of patients, the need for prandrial insulin and lower postsurgical weight loss may hamper the beneficial effects of BS on glycemic control.