BACKGROUND: There is a paucity of modern data on the impact of high tacrolimus levels early after kidney transplantation.

MATERIAL AND METHODS: This study analyzed the impact of various trough levels of tacrolimus in the first 2 weeks post-transplant on rates of delayed graft function (DGF), length of stay (LoS), hyperkalemia, hyperglycemia, and biopsy-proven acute rejection (BPAR) rates in the first 3 months post-transplant in a retrospective single-center cohort of patients. Patients were divided into 4 groups based on the average of two highest 12-hour trough tacrolimus levels: <10 ng/mL, 10–12 ng/mL, 12–15 ng/mL, >15 ng/mL.

RESULTS: The incidence of DGF was noted to be significantly higher in the <10 ng/mL, >15 ng/mL and the 12–15 ng/mL tacrolimus groups as compared to the 10–12 ng/mL group (49%, 25% and 4%, respectively, p=<0.0001). Mean LoS was also noted to be significantly higher in the >15 ng/mL tacrolimus group as compared to the 10–12 ng/mL group (7.4 days and 6.1 days respectively, p=0.0007). There was no difference in the rates of hyperkalemia, hyperglycemia or BPAR.

CONCLUSIONS: This is a modern confirmation of the association between higher tacrolimus levels early after kidney transplantation and increased rate of DGF and increased LoS.

Keywords: Delayed Graft Function, acute rejection, Calcineurin Inhibitor Toxicity