Adults with long-duration type 2 diabetes have blunted glycemic and β-Cell function improvements after bariatric surgery

Objective This study investigated the effect of type 2 diabetes duration on glucose regulation 24 months post-bariatric surgery. Methods Twenty-seven adults with short-(<5 years) and long-duration (≥10 years) type 2 diabetes received a mixed-meal tolerance test at baseline and 24 months postsurgery. Body weight, insulin sensitivity, first-and second-phase meal-stimulated insulin secretion, disposition index (i.e., DI or pancreatic β-cell function), and incretin responses were examined. Results Adults with short-duration type 2 diabetes had better HbA_1c, greater insulin secretory capacity, and greater DI compared with adults with long-duration type 2 diabetes, despite similar weight loss and incretin responses. Diabetes duration correlated with smaller improvements in HbA_1c and DI but not weight loss. Conclusions Enhanced β-cell function characterizes the effect of bariatric surgery in adults with diabetes for <5 years, independent of weight loss or incretins. Additional therapy postsurgery may be required to improve glycemia for people with long-standing type 2 diabetes.