Correlation of renal function with intra-patient variability of tacrolimus concentration among recipients of renal transplants: a 10-year study.

Abstract

Background: Tacrolimus is one of the most commonly used basic immunosuppressants nowadays, but the high variability of tacrolimus blood concentration often leads to kidney transplant recipients frequently experiencing drug concentrations above or below the target concentration, resulting in renal toxicity or rejection of the transplanted kidney. The aim of this study is to explore the correlation of renal function with intra-patient variability (IPV) of tacrolimus blood concentration among recipients of renal transplants at 1-, 3-, 5-, and 10-year post-transplantation.

Methods: Recipients of renal transplants who were treated with tacrolimus for immunosuppression at the Shanghai General Hospital between January 2001 and December 2009, and followed up until 2019 were included in this retrospective study. Demographic characteristics and laboratory investigation results at their 1-, 3-, 5-, and 10-year follow-up visits were collected from their hospital medical records. Patients were divided into a low or high IPV group based on the IPV of their tacrolimus concentrations.

Results: A total of 167 kidney transplant recipients were included in the study. At the 3-year follow-up visit, patients in the low IPV group had significantly lower blood urea nitrogen (BUN) (6.3±1.8 vs. 8.2±6.2 µmol/L, P=0.04), serum creatinine (Scr) (88.8±23.6 vs. 104.8±39.6 µmol/L, P=0.009), and blood uric acid (UA) (329.1±80.2 vs. 375.9±95.1 µmol/L, P=0.004), as well as significantly higher estimated glomerular filtration rate (eGFR) values than patients in the high IPV group. Blood UA levels were significantly lower in patients in the low IPV group than the high IPV group at the 10-year follow-up (362.7±92.6 vs. 398.5±105.2 µmol/L, P=0.042). There was no significant difference between the low and high IPV groups with respect to BUN, Scr, UA, or eGFR at the 1- and 5-year follow-up.

Conclusions: Recipients of renal transplants with lower IPV in tacrolimus concentration appeared to have better renal function over time. Controlling IPV may contribute to improved renal outcomes post-transplantation.