Effect of Conversion From Twice-daily to Once-daily Tacrolimus on Glucose Intolerance in Stable Kidney Transplant Recipients

Background. Tacrolimus is an established immunosuppressant for the prevention and treatment of allograft rejection in organ transplantation. However, tacrolimus therapy also has several adverse effects. The main aim of this study was to evaluate the effect of conversion from twice-daily tacrolimus (tacrolimus-BID) to once-daily tacrolimus (tacrolimus-OD) on glucose intolerance in stable kidney transplant patients. Methods. The study comprised 43 kidney transplant recipients with stable renal function. The same 1 mg:1 mg dose conversion was used for all patients. Follow-up, which included clinical evaluation and laboratory testing, was performed at 30, 60, and 120 days after conversion. The parameters for which the baseline and end-point values were determined included homeostasis model assessment of beta-cell function (HOMA-B) scores, hemoglobin A(1c) (HbA(1c)) levels, serum insulin levels, and fasting glucose levels. Results. The tacrolimus trough levels did not differ significantly at 120 days after conversion. There was a significant increase in serum insulin level at 120 days after conversion (baseline, 5.6 +/- 2.7 mu U/mL; end point, 6.6 +/- 3.4 mu U/mL; P < .009). The HOMA-B score slightly increased (baseline, 58.7 +/- 33.1; end point, 65.6 +/- 32.8; P = .091) at 120 days after conversion, indicating beta-cell function. Serum creatinine concentration, blood glucose level, and HbA(1c) level did not change significantly during follow-up examinations. Episodes of acute rejection or graft loss did not occur. Conclusion. The results of this study suggests that conversion from tacrolimus-BID to tacrolimus-OD may benefit kidney transplant patients with glucose intolerance because of improved insulin secretion. Further studies involving a larger sample population and longer follow-up time are required to verify the results of this study.