Beta Cell Function and Insulin Resistance After Conversion from Tacrolimus Twice-Daily to Extended-Release Tacrolimus Once-Daily in Stable Renal Transplant Recipients.

BACKGROUND Post-transplantation diabetes mellitus is a major metabolic adverse effect of tacrolimus (TAC). The objective of this study was to determine if the conversion from tacrolimus twice-daily (TAC-BID) to extended-release tacrolimus once-daily (TAC-OD) in stable renal transplant recipients had any effect on beta cell function (HOMA-b), insulin resistance (HOMA-IR), patient preference, and expense. MATERIAL AND METHODS Twenty-eight renal transplant recipients were recruited and converted from TAC-BID to TAC-OD at the same dose. Primary outcomes were beta cell function and insulin resistance in stable renal transplant recipients at 4, 8, and 16 weeks after conversion. Secondary outcomes were patient satisfaction and expense of medication. RESULTS No significant change in the HOMA-β and HOMA-IR was found in any of the 28 renal transplant recipients. However, HOMA-β increased from 60 (37.33, 109.71) to 78.5 (44.3, 108.4) (p=0.02) in 15 patients who had the conversion within 4 years after renal transplantation. In multivariate regression analysis, the conversion from TAC-BID to TAC-OD significantly increased HOMA-b at 4 months at 1.21 mIU/mmol (95%CI 0.54-1.88 mIU/mmol, p=0.01) in this subgroup. The renal transplant recipients reported the conversion was more satisfactory and cost of treatment was comparable. CONCLUSIONS In short-term follow-up, conversion from TAC-BID to TAC-OD is safe in stable renal transplant recipients and might be beneficial in term of improved beta cell function in the early years after renal transplantation. The conversion caused comparable cost and was preferred by renal transplant recipients.