Tacrolimus intrapatient variability and latent virus reactivation after kidney transplantation: A retrospective study comparing prolonged-release and immediate-release tacrolimus formulations.

ObjectiveThis study explored the differences in intrapatient variability of tacrolimus between prolonged-release and immediate-release formulations and evaluated the association between tacrolimus intrapatient variability and reactivation of BK virus and cytomegalovirus in kidney transplant recipients.MethodsThis retrospective observational study included 270 kidney transplant recipients receiving either prolonged-release tacrolimus or immediate-release tacrolimus. Receiver operating characteristic curve analysis identified tacrolimus intrapatient variability cutoff values associated with viral reactivation. Logistic regression analyses identified predictors of BK virus and cytomegalovirus reactivation.ResultsThe prolonged-release tacrolimus group had significantly lower tacrolimus intrapatient variability than the immediate-release tacrolimus group (p < 0.001). No significant differences were observed in BK virus and cytomegalovirus reactivation rates. Receiver operating characteristic curve analysis identified tacrolimus intrapatient variability cutoffs of 0.268 for BK virus and 0.261 for cytomegalovirus. High tacrolimus intrapatient variability was significantly associated with increased BK virus and cytomegalovirus reactivation. Logistic regression showed that high tacrolimus intrapatient variability was significantly associated with BK virus and cytomegalovirus reactivation. Multivariate analysis confirmed an independent association between high tacrolimus intrapatient variability and cytomegalovirus reactivation.ConclusionsTacrolimus intrapatient variability may predict reactivation of latent viral infection after kidney transplantation. Although viral reactivation rates were similar between tacrolimus formulations, prolonged-release tacrolimus showed lower tacrolimus intrapatient variability levels, suggesting that fluctuations in tacrolimus exposure might increase the risk of viral reactivation.