Supplementary Material for: Association between non-invasive liver biomarkers and graft outcomes in kidney transplantation recipients

Introduction: Although studies have suggested that metabolic risk profiles are prognostic factors in kidney transplantation recipients (KTRs), the prognostic value of fatty liver, a known surrogate of metabolic risk, in KTRs remain to be elucidated. The objective of this study was to investigate the association between non-invasive liver biomarkers used to assess hepatic steatotic and fibrotic burdens and graft outcomes in KTRs.
Methods: A total of 3,092 patients who underwent deceased or living donor kidney transplantation (KT) between January 2000 and December 2022 were enrolled. Postoperative hepatic fibrotic burdens of KTRs were assessed using the Fibrosis-4 (FIB-4) score and the non-alcoholic fatty liver disease fibrosis score (NFS). The primary outcome was a composite of 50% estimated glomerular filtration rate (eGFR) decline and graft failure. Secondary outcomes included individual outcomes of 50% eGFR decline, graft failure, and acute rejection.
Results: For the primary outcome, during a mean follow-up of 6.0 years, the composite outcome occurred in 519 (16.8%) participants. When stratified into three groups according to FIB-4 score categories, the highest score group (FIB-4≥2.67) had a 2.05-fold (95% confidence interval [CI], 1.44-2.91; P<0.001) higher risk of the composite outcome compared to the lowest score group (FIB-4<1.30). Furthermore, the highest score group showed higher risk of the secondary outcomes, with hazard ratios (95% CI) of 1.75 (1.16-2.66), 1.62 (1.06-2.46), and 2.23 (1.43-3.46) for 50% eGFR decline, acute rejection and graft failure, respectively. Similar findings were observed for NFS.
Conclusions: Higher hepatic fibrotic burdens were associated with unfavorable graft outcomes in KTRs.