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.