Glucose metabolism after pancreas transplantation: Cyclosporine versus tacrolimus

Background. The results of the new immunosuppressants in simultaneous pancreas-kidney transplantation (SPK) concerning organ survival and rejection rates are excellent. Tacrolimus as well as cyclosporine are assumed to be diabetogenic; however, there are no comparative studies investigating their effects on glucose metabolism. Methods. One hundred thirty-six type 1 diabetic patients who had undergone successful SPK were investigated. Glucose and insulin levels during an oral glucose tolerance test as well as hemoglobin (Hb) A1c were analyzed. Investigations were performed early (3 months, n=136) and late (3 years, n=83) after transplantation. Graft recipients were grouped according to the first-line immunosuppression: group 1, cyclosporine; group 2, tacrolimus. There were no differences concerning age, gender, body mass index, and renal function between the groups. Results. Early after transplantation, there was no difference between the groups concerning fasting glucose, HbA1c levels, basal and stimulated insulin secretion, and incidence of normal glucose tolerance. Late after transplantation, the incidence of a normal glucose tolerance tended to be lower (70% vs. 78%), whereas HbA1c (5.3% vs. 5.0%) and fasting glucose (81 vs. 78 mg/dL) levels tended to be higher in tacrolimus-treated patients. However, these differences were not significant. Insulin secretion was not reduced in the tacrolimus group. Conclusions. Concerning glucose metabolism and secretory capacity of the pancreas graft, no significant differences were found comparing tacrolimus- versus cyclosporine-treated graft recipients.