β-Cell Function and Insulin Dynamics in Obese Patients With and Without Diabetes After Sleeve Gastrectomy

Improved β-cell function seems to be essential for better glucose homeostasis after Roux-en-Y gastric bypass but is less studied after sleeve gastrectomy (SG). We evaluated the effects of SG on β-cell function in obese patients with diabetes (DM group) and without (control group) in response to both oral and intravenous glucose stimulation. The DM group demonstrated impaired insulin sensitivity and insulin response to glucose before surgery. The insulin sensitivity index of both groups significantly improved after SG. In addition, the insulin response to glucose (early insulinogenic index in oral glucose tolerance test and acute insulin response to glucose in an intravenous glucose tolerance test) increased in the DM group but decreased in the control group. As a result, β-cell function improved significantly in both groups after SG since the disposition index (DI) increased in both. However, the DI of the DM group was not restored to the level of control group up to 1 year after SG. Our results support that obese patients, with and without diabetes, could benefit from SG in β-cell function. For obese patients at risk for or who have been diagnosed with diabetes, interventions should be recommended early to preserve or restore β-cell function, and SG could be an effective choice. Further studies are needed for long-term effects.