Insulin response to oral stimuli and glucose effectiveness increased in neuroglycopenia following gastric bypass.

Abstract

Hyperinsulinemic hypoglycemia with neuroglycopenia is a rare complication following Roux-en-Y gastric bypass (RYGB) surgery for weight management. Insulin secretion and action in response to oral and intravenous stimuli in persons with and without neuroglycopenia following RYGB are evaluated in this study. Cross-sectional cohort studies were performed at a single academic institution to assess insulin secretion and action during oral mixed meal tolerance test and intravenous glucose tolerance test (IVGTT). Insulin secretion was increased more following oral mixed meal than intravenous glucose in individuals with neuroglycopenia compared to the asymptomatic group. Reduced insulin clearance did not contribute to higher insulinemia. Glucose effectiveness at zero insulin, estimated during the IVGTT, was also higher in those with neuroglycopenia. Insulin sensitivity did not differ between groups. Increased beta-cell response to oral stimuli and insulin-independent glucose disposal may both contribute to severe hypoglycemia after RYGB.