Early Determination of Tacrolimus Concentration–Dose Ratio Identifies Risk of Allograft Loss in Kidney Transplantation

Introduction: Fast tacrolimus–metabolizing kidney transplant recipients (KTRs) (i.e., tacrolimus trough-level/total daily dose [C0/D < 1.05]) have poorer allograft function; however, their identification in a real-life setting is challenging. We investigated the reproducibility of tacrolimus meta...

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Main Authors: Christophe Masset, Marine Lorent, Clarisse Kerleau, Claire Garandeau, Aurélie Houzet, Simon Ville, Diego Cantarovich, Gilles Blancho, Magali Giral, Jacques Dantal, Julien Branchereau, Agnès Chapelet, Florent Delbos, Clément Deltombe, Lucile Figueres, Charles Ronsin, Thibault Letellier, Clémence Petit, Caroline Gourraud-Vercel, Laurent Nicolet, Christine Kandel-Aznar, Ismaël Chelghaf, Aurélie Meurette, Karine Renaudin, Alexandre Walencik
Format: Article
Language:English
Published: Elsevier 2025-05-01
Series:Kidney International Reports
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Online Access:http://www.sciencedirect.com/science/article/pii/S2468024925001032
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Summary:Introduction: Fast tacrolimus–metabolizing kidney transplant recipients (KTRs) (i.e., tacrolimus trough-level/total daily dose [C0/D < 1.05]) have poorer allograft function; however, their identification in a real-life setting is challenging. We investigated the reproducibility of tacrolimus metabolic status during the first months after transplantation and its association with long-term allograft outcomes. Methods: All KTRs between 2000 and 2019 with a functional allograft at 1 month and receiving tacrolimus in our center were included. Fast or slow tacrolimus metabolizers were classified according to the time spent with a C0/D < 1.05 (> 75% = High, < 25% = Low) at various time points posttransplantation. We first determined the earliest accurate time for patient categorization by investigating C0/D variability during the first months. Second, a multivariate cause-specific Cox model studying allograft outcomes was performed in groups identified by their status determined from the earliest accurate timepoint after transplantation. Results: Among 1979 patients included in the analysis, 2 months was the earliest accurate timepoint to determine High patients (85% of High patients identified at 2 months remained High long-term, Brier score = 0.06). Multivariate analysis revealed that High patients determined at 2 months (n = 499) had a significantly higher risk of allograft loss (cause-specific hazard ratio [CS-HR] = 2.00, 95% confidence interval [CI] = 1.48–2.69) and allograft rejection (CS-HR = 1.71, 95% CI = 1.15–2.54) than Low patients after adjustment for confounding factors. Moreover, allograft function was lower in High patients (46.7 vs. 52.9 ml/min, at 3 years, P < 0.0001) with a higher proportion of chronic vascular lesions at 1 year. Conclusion: C0/D is a simple and pragmatic tool capable of identifying patients at risk of rejection and allograft failure as early as the second month posttransplantation.
ISSN:2468-0249