Impaired glucose tolerance in cyclosporine-prednisolone-treated renal graft recipients

In 33 renal transplant patients, an intravenous glucose tolerance test (IVGTT) was performed, and fasting plasma C-peptide concentrations analyzed. Nineteen of the patients were on treatment with cyclosporine-prednisolone (CsA-Po), and 14 were treated with azathioprine-prednisolone (Aza-Po). In the Aza-Po group, the K-values at IVGTT were normal in 13/14, but in the CsA-Po group they were only normal in 9/19 (P = 0.02). The fasting C-peptide levels were significantly higher in the CsA-Po group (P less than 0.001). within this group, there was no correlation between C-peptide level and serum-creatinine concentration, i.e. retention of C-peptide due to decreased renal function as judged by serum creatinine level was not suspected. Intrinsic prednisolone clearance was determined in the CsA-Po patients and was found to be lower than that previously described in Aza-Po patients. However, between those CsA-Po-treated patients with a pathologic K-value at IVGTT and those with a normal K-value there was no difference in prednisolone clearance, fasting C-peptide levels, CsA dose, or serum-creatinine concentrations. The pathophysiology of the cyclosporine-induced glucose intolerance is uncertain, and increased insulin resistance is possible.