Association of Metabolic Dysfunction-Associated Steatotic Liver Disease with Renal Allograft Failure in Kidney Transplant Recipients

Background: Metabolic dysfunction-associated steatotic liver disease (MASLD) has been recently established to more accurately define and classify steatotic liver disease (SLD). MASLD is associated with increased risks of cardiovascular disease and chronic kidney disease. However, its impact on kidney transplant (KT) outcomes remains less understood. We aimed to investigate the association between MASLD and long-term KT outcomes. Methods: KT recipients who underwent a national health screening program from 2009 to 2017 were identified using data from the Korean National Health Insurance Service, with follow-up until 2021. MASLD was defined based on cardiometabolic criteria and the fatty liver index, incorporating waist circumference, body mass index, serum triglycerides, and gamma-glutamyl transferase levels. Recipients with other specific liver disease etiologies were classified separately. Cox proportional hazard models were used to evaluate the association between MASLD and two outcomes: death-censored graft failure and all-cause mortality. Results: Among 8,268 KT recipients, 1,999 (24.2%) had MASLD, while 24 and 417 recipients had alcohol-related/associated liver disease and other liver disease, respectively. The incidence rates of graft failure and mortality were significantly higher in the MASLD group compared to those without SLD (graft failure 16.37 vs. 10.64 per 10,000 person-years, P <.001 for log-rank; mortality 12.44 vs. 8.77, P <.001). MASLD was associated with a 1.56-fold (95% confidence interval 1.32–1.87) higher risk of graft failure and a 1.43-fold (1.18–1.73) higher risk of mortality by unadjusted analyses. After adjusting for multiple covariates, including demographics, lifestyle, comorbidities, estimated GFR, and proteinuria, adjusted hazard ratios for graft failure and mortality were 1.28 (1.06–1.54) and 1.01 (0.83–1.23). Subgroup analyses consistently demonstrated the association between MASLD and increased graft failure risk, with no significant interactions. Conclusion: This study identifies MASLD as a significant risk factor for graft failure in KT recipients. These findings underscore the need for early identification and risk stratification for MASLD in this population. Targeted management strategies for MASLD may help improve long-term kidney transplant outcomes.