Glucose metabolism and incretins level in morbidly obese patients and in patients after biliopancreatic diversion performed for morbid obesity

We’ve studied a carbohydrate metabolism in morbidly obese (MO) patients and the patients after bariatric surgery. The patients of the 1st group had BMI>40 (n=22) and no history of diabetes mellitus. Patients after biliopancreatic diversion (BPD) performed for MO were included in the 2nd group (n=23). The 3rd group was a control group of normal weight healthy subjects (n=22). Blood glucose levels, insulin, GLP-1, GIP and glucagon during the OGTT (with 75 g of glucose) at 0, 30, 60 and 120 minutes were measured in all patients. In MO group fasting glucose levels were the highest. Impaired glucose metabolism was revealed in 68.2% of patients (n=10). Impaired fasting glucose (IFG) was diagnosed in 4 cases (18.2%), impaired glucose tolerance (IGT) in 11 patients (50%). In the BPD postprandial blood glucose levels (120 min) were lower if compared to the other groups. In 4 individuals (17.4%) we found postprandial hypoglycemia (<2.8 mmol/l). Patients of the MO group had the highest fasting insulin levels and HOMA-IR (p<0.001). The maximum of insulin concentration was seen on minute 30 of the OGTT in the 2nd and 3rd groups, and it was significantly higher in the post-bariatric patients (p=0.026). In MO group the maximum of the plasma insulin levels were on the 60th minute and were still elevated after 120 minutes. Fasting and stimulated (on the 30th minute) levels of GLP-1 were significantly higher after BPD (р=0.037 and p=0.022 at 0 and 30 min, respectively). Morbidly obese patients had higher fasting and stimulated GIP. Fasting glucagon concentrations were similar in the surgical and control groups, while the people with MO had higher initial levels of glucagon (p=0.013) and it was not suppressed during the OGTT (p=0.076). Glucose intolerance and insulin resistance incidence was higher in MO patients. Hyperglucagonemia, increased GIP and decreased GLP-1 levels are observed in MO patients. Stimulated plasma insulin and GLP-1 concentrations were significantly increased in patients who underwent BPD, and may cause postprandial hypoglycemia.