Conversion from tacrolimus to cyclosporin is associated with a significant improvement of glucose metabolism in patients with new-onset diabetes mellitus after renal transplantation

Background. The incidence of new-onset posttransplant diabetes mellitus (PTDM) is increased in renal transplant patients treated with tacrolimus. Methods. We retrospectively analyzed fasting plasma glucose and HbA1c levels as well as the dose of glucose-lowering agents in 34 renal transplant patients converted from tacrolimus to cyclosporine (CsA) for PTDM. Diabetes was defined according to current guidelines as repeated fasting plasma glucose (FPG) levels >= 126 mg/dL. Results. At conversion, 11 patients received insulin, 5 received oral agents, and 18 had no glucose-lowering therapy. Fasting plasma glucose levels decreased from 146 64 mg/dL at conversion to 111 +/- 26 mg/dL at 3 months and 104 21 mg/dL at 12 months (P < .001). HbA1c levels decreased from 6.8 +/- 0.8% at conversion to 6.0 +/- 0.6% at 12 months (P = .001). Insulin was stopped in 3, the dose reduced in 7, and remained stable in 1 of the patients. The average daily insulin dose among these patients was reduced from 31 +/- 17 units at conversion to 13 +/- 12 units at 12 months (P < .05). There was no significant change in the number of patients treated with oral glucose-lowering agents. Diabetes reversed (fasting plasma glucose <= 125 mg/dL without glucose-lowering therapy) in 44% (95% confidence interval, 23% to 64%) of patients during the first year after conversion (P < .001). Graft function, blood pressure, and lipid levels remained stable after conversion but the proportion of patients receiving lipid-lowering therapy increased from 18% to 49% (P < .01). Conclusions. Conversion from tacrolimus to CsA for PTDM was associated with a marked improvement in glucose metabolism and frequent reversal of diabetes.