Association of Therapeutic Monitoring of Tacrolimus with Laboratory Markers of Kidney Function in Receptors of Kidney Allograft

Introduction: Kidney transplantation is the most commonly performed type of transplant in Brazil. Tacrolimus is one of the primary drugs used in post-transplant immunosuppressive therapy, and one of its main adverse effects is nephrotoxicity. Laboratory tests to assess renal function are of great importance in monitoring post-kidney transplant patients, helping to diagnose events indicative of graft dysfunction. Objective: !e present study aimed to evaluate the association between laboratory changes in renal function and blood levels of tacrolimus in post-kidney transplant patients. Methods: Observational, analytical and cross-sectional study. !e results of blood levels of tacrolimus and measurements of urea, creatinine and estimated Glomerular Filtration Rate (eGFR) were analyzed, as well as the sociodemographic data of kidney transplant recipients followed at a university hospital who underwent laboratory tests between months from January 2021 to July 2022 in a period close to 1 year after the transplant. !e variables analyzed in the research were collected from the patient's medical records and subsequently analyzed; the statistical analyses considered p < 0.05. !e project was approved by the Ethics Committee of the Walter Cantídio University Hospital under opinion number 5,436,434 and CAAE number 57396622.1.0000.5045. Results: !e sample was mainly composed of males, mixed race, with an average age of 51.5 years (SD ± 12.5) and from cities in the interior of Ceará. Regarding the percentage of patients with laboratory changes, 50.62% (n = 45) showed changes in tacrolimus blood levels. 56.79% (n = 46) had changes in serum creatinine levels, 49.38% (n = 40) had changes in serum urea levels, and 59.26% (n = 48) had altered eGFR. !e correlation analyses suggested a low signi#cance between variations of the variables studied. Conclusion: !e results indicate no relationship between variations in tacrolimus blood concentrations and the appearance of changes in the results of classic renal biomarkers at the end of the #rst year post-transplant. However, it is necessary to carry out new studies to understand better the impact of changes in blood levels of tacrolimus on the renal function of renal allograft recipients.