Glucose homeostasis in mucoviscidosis

In patients with cystic fibrosis (CF) of the pancreas an endocrine imbalance especially of insulin secretion due to progressive structural abnormalities of the pancreas must be expected. 30-75 percent of CF-patient exhibit impaired oral glucose tolerance tests (oGTT). Deterioration of the glucose homeostasis leads to a secondary diabetes mellitus that mimics a type II diabetes in the early stage, in the later course of disease it resembles a type I diabetes with absolute insulinopenia. In this study glucose homeostasis was investigated after an oral glucose load with 1.75 g glucose/kg bodyweight. Glucose, C-peptide and insulin were measured during 180 minutes. 32 nondiabetic CF-patients were studied. 16 patients revealed an impaired oral glucose tolerance according to the criteria of the National Diabetes Data Group. 6 patients showed a normal glucose tolerance and 10 patients with normal fasting and 120 minute glucose concentrations were hyperglycemic at midtest determinations. Impaired oGTTs were observed in malnourished CF-patients in a higher rate than in normal weight patients. A delayed and exceeded C-peptide and insulin response to the oral glucose load was determined with deteriorating glucose tolerance. Glucose values did not drop to fasting values at the 180 minute determination in cases of impaired oral glucose tolerance.