Background
Enhanced insulin sensitivity is commonly seen following Roux-en-Y gastric bypass surgery (RYGB) whereas symptomatic hypoglycemia
post-RYGB seems to occur infrequently. It is unclear how different plasma glucose and insulin responses are in patients with
symptomatic hypoglycemia (SX-RYGB) versus those who remain asymptomatic (ASX-RYGB), nor when compared with non-surgical controls
with varying degrees of insulin sensitivity.
Methods
Plasma glucose and insulin concentrations were determined following a 75-g oral glucose challenge in five groups: symptomatic
and asymptomatic patients following RYGB (n = 9 each) and overweight/obese controls, divided into three subgroups (n = 30 each) on the basis of degree of insulin sensitivity measured by the insulin suppression test.
Results
SX-RYGB group had higher 30-min glucose after oral glucose compared with the ASX-RYGB group (p = 0.04). The two groups did not differ in peak glucose and insulin concentrations, nadir glucose concentration, or insulin-to-glucose
ratio 30 min after oral glucose. These values were significantly different from the three control groups, and peak insulin
concentrations post-RYGB were increased at every degree of insulin sensitivity as compared with the control groups.
Conclusions
Plasma glucose and insulin responses to oral glucose in patients with symptomatic hypoglycemia post-RYGB are minimally different
when compared to individuals who remain asymptomatic, and both groups demonstrate hyperinsulinemia out of proportion to their
degree of insulin sensitivity.
Keywords Gastric bypass - Hypoglycemia - Obesity - Hyperinsulinism - Insulin resistance
The authors have no commercial interest to disclose.