Background: There is an interest in understanding the association between early calcineurin inhibitors exposure post-liver transplantation (LT) and long-term outcomes. We aimed to analyze this association exploring median calcineurin inhibitor levels and intrapatient variability (IPV) in a multicenter, retrospective cohort.
Methods: Tacrolimus (Tac) and Cyclosporine (CsA) levels obtained during the first 15 days post-LT were collected. High immunosuppression (IS) was considered as a median of Tac, CsA blood trough levels 12 hours after drug administration, or blood levels 2 hours after drug administration higher than 10, 250, or 1200 ng/mL, respectively, or a peak of Tac >20 ng/mL. Optimal IS was defined as a median of Tac, CsA blood trough levels 12 hours after drug administration, or blood levels 2 hours after drug administration levels between 7 and 10, 150 and 250, or 800 and 1200 ng/mL. Low IS was defined as below the thresholds of optimal IS. IPV was estimated during the first 15 days post-LT.
Results: The study included 432 patients with a median follow-up of 8.65 years. IS regimen was based on either Tac or CsA in 243 (56.3%) and 189 (43.8%), respectively. There were no differences in terms of graft loss among low versus optimal and high IS groups (P = 0.812 and P = 0.451) nor in high versus low IPV (P = 0.835). Only viral hepatitis and arterial hypertension were independently associated with higher graft loss (hazard ratio = 1.729, P = 0.029 and hazard ratio = 1.570, P = 0.021).
Conclusions: In contrast to what has previously been reported, no association was found between very early postoperative over IS or high IPV and long-term outcome measures following LT. Strategies aimed at reducing these long-term events should likely focus on other factors or on a different IS time window.