Insulin sensitivity, insulin secretion and glucose effectiveness in diabetic and non-diabetic cirrhotic patients

In cirrhotic patients with normal fasting glucose levels both insulin insensitivity and a blunted early insulin response to oral glucose are important determinants of the degree of intolerance to oral glucose. It is not known whether the ability of hyperglycaemia per se to enhance glucose disposal (glucose effectiveness) is also impaired. It is also unclear whether overt diabetes is due to: (1) more marked insulin insensitivity; (2) impaired insulin secretion; (3) reduced glucose effectiveness; or (4) a combination of these mechanisms. We used the "minimal model" to analyse the results of a 3-h intravenous glucose tolerance test to assess glucose effectiveness, insulin sensitivity and insulin responses in 12 non-diabetic cirrhotic patients, 8 diabetic cirrhotic patients and 10 normal control subjects. Fasting blood glucose levels were 4.8 +/- 0.2, 7.5 +/- 0.6 and 4.7 +/- 0.1 mmol/l, respectively. Fasting insulin and C-peptide levels were higher in both cirrhotic patient groups compared with control subjects. The glucose clearance between 6 and 19 min after i.v. glucose was lower in both cirrhotic groups (non-diabetic, 1.56 +/- 0.14, diabetic, 0.76 +/- 0.06, control subjects, 2.49 +/- 0.16 min-1%, both p < 0.001 vs control subjects). Serum insulin peaked at 3 and 23 min in the non-diabetic cirrhotic patients and control subjects; both peaks were higher in the non-diabetic cirrhotic patients and showed a delayed return to basal levels.(ABSTRACT TRUNCATED AT 250 WORDS)