Endocrine Abstracts

Objective: To compare the impact of 4 surgical procedures (mini gastric bypass [MGB], sleeve gastrectomy [SG], ileal transposition [IT], and transit bipartition [TB]) versus medical management on gut peptide secretion, beta cell function, and resolution of hyperglycaemia in type 2 diabetes (T2DM).

Research design and methods

A mixed-meal tolerance test (MMTT) was administered 6–24 months after each surgical procedure (mini gastric bypass [MGB], sleeve gastrectomy [SG], ileal transposition [IT], and transit bipartition [TB], n = 30 in each group) and the result was compared to matched lean (n = 30) and obese (n = 30) T2DM participants undergoing medical management

Results: MGB and IT participants had a greater increase in plasma glucose concentration following MMTT than SG and TB participants. MGB participants exhibited the greatest increase in the incremental area under the curve of plasma glucose concentration above baseline (∆G_0–120) (P < 0.0001). Insulin sensitivity was comparable across surgical groups, and statistically greater in surgical participants than in obese nonsurgical participants (P < 0.0001). Beta cell responsiveness to glucose was greater in SG and TB than in MGB and IT participants (P < 0.001) despite a smaller increase in ∆GLP-1_0–120 relative to IT. Postoperative beta cell function was the strongest predictor of hyperglycaemia resolution.

Conclusions: The present study demonstrated that the level of beta cell function after bariatric surgery is the strongest predictor of hyperglycaemia resolution. The study also demonstrates a disconnection between postprandial GLP-1 levels and beta cell function among the studied surgical procedures.