Abstract

Background: Currently, the recommended tacrolimus (TAC) trough level (Cmin) after liver transplantation (LT) is 6–10 ng/mL (when associated in triple immunosuppressive therapy). However, few studies have achieved the lower limit of this range, especially below 7 ng/mL. This study evaluated the efficacy of a target TAC Cmin of 4–7 ng/mL after LT. Methods: Of 1677 LTs performed between 2002 and 2017, 904 LT cases were analyzed. The cases were categorized into the following 3 groups and compared: low- (n = 247, 27.3%), intermediate- (n = 344, 37.9%), and high-exposure groups (n = 313, 34.5%) with TAC Cmin of 4–7 ng/mL, 7–10 ng/mL, and >10 ng/mL, respectively. In addition, propensity score matching was performed to reduce heterogeneity and population bias. Results: At months 1 and 3, when compared with the 2 other groups, the low-exposure group had similar grafts ( P = 0.75) and patient ( P = 0.77) survival, but lower alanine aminotransferase ( P < 0.001), bilirubin ( P < 0.001), international normalized ratio ( P = 0.046), and creatinine ( P < 0.001) levels. After propensity score matching, the bilirubin ( P < 0.001) and creatinine ( P = 0.001) levels in the low-exposure group still improved at months 3, but the graft ( P = 0.86) and patient ( P = 0.99) survival were still similar. Conclusions: A TAC Cmin of 4–7 ng/mL seems safe and capable of improving graft and kidney function. This finding should be confirmed in a prospective randomized trial.