Recovery of the incretin effect in type 2 diabetic patients after biliopancreatic diversion.

CONTEXT Bariatric surgery often results in remission of the diabetic state in obese patients. Increased incretin effect seems to play an important role in the glycemic improvements after Roux-en-Y gastric bypass, but the impact of biliopancreatic diversion (BPD) remains unexplored. OBJECTIVE The objective was to elucidate the effect of BPD on the incretin effect and its interplay with beta-cell function and insulin sensitivity (IS) in obese subjects with type 2 diabetes (T2DM). DESIGN, SETTING AND PATIENTS Twenty-three women were studied: a control group of 13 lean, normal glucose-tolerant women (lean NGT) studied once and 10 obese patients with T2DM studied before, 1 and 12 months after BPD. INTERVENTION The ObeseT2DM group underwent BPD. MAIN OUTCOME MEASURES The main outcome measure was the change in incretin effect as measured by the isoglycemic intravenous glucose infusion test. Secondary outcomes encompassed IS and beta-cell function. RESULTS At baseline, the incretin effect was lower in obese T2DM compared to lean NGT (P < .05). One month after BPD, the incretin effect was not changed, but at 12 months it reached the level of the lean NGT group (P > .05). IS improved (P < .05) 1 month after BPD and at 12 months it resembled the levels of the lean NGT group. Insulin secretory rate and beta-cell glucose sensitivity increased after BPD and achieved levels similar to lean NGT group 1 month after BPD and even higher levels at 12 months (P < .05). CONCLUSIONS BPD has no acute impact on the reduced incretin effect, but 12 months after surgery the incretin effect normalizes alongside normalization of glucose control, IS and beta-cell function.