Association of BMI with Hepatic Steatosis, Fibrosis, and Inflammation: Insights from a Deceased Donor Liver Cohort Study Based on the UNOS Database

Background: While the prevalence of obesity and its negative effects on graft steatosis in liver transplantation are well recognized, the impact of obesity in the absence of hepatic steatosis, fibrosis, and inflammation in deceased donor livers remains unclear. This knowledge gap may affect the decision to adopt a transplant strategy and influence the following outcomes. Methods: A donor population-based cohort study was performed on 35,529 donors who received liver biopsy from 1987 to 2024. Donor BMI was categorized and assessed for its association with liver conditions, including macrovesicular steatosis, microvesicular steatosis, liver fibrosis, and portal infiltrates. Multivariable logistic regression and restricted cubic spline (RCS) regression models were employed to explore both linear and nonlinear relationships between BMI and the specified liver conditions. Results: In a cohort of 35,529 donors, donor livers from higher BMI groups exhibited higher percentages of macro-steatosis, micro-steatosis,advanced fibrosis and portal infiltrate.Logistic regression indicated obesity as an independent predictor of liver histology assessment: for higher risk with moderate-servere macro-steatosis (OR 2.29, 95% CI 2.11–2.49, p < 0.001),moderate-servere micro-steatosis (OR 1.71, 95% CI 1.57–1.87, p < 0.001), portal infiltrate (OR 1.37, 95% CI 1.3–1.45, p < 0.001) and advanced fibrosis (OR 1.04, 95% CI 0.94–1.14, p < 0.001). Restricted cubic spline regression depicted J-shaped with moderate-servere macro-steatosis and portal infiltrate,a U-shaped advanced fibrosis, and a upside down U-shaped with moderate-servere micro-steatosis,P for for nonlinearity <0.0001),respectively. Subgroup analyses identified interactions with factors such as gender, hypertension, and hepatitis C, highlighting BMI’s complex influence on liver histology and reinforcing its role in liver donor evaluation. Conclusion: This donor population-based cohort study found a different association pattern between donor BMI and liver biopsy outcomes,integrating BMI into donor liver assessments could enhance decision-making during transplantation, potentially reducing organ discard rates and improving transplant success by identifying high-risk organs earlier.

donor BMI; macro-steatosis and micro-steatosis; liver fibrosis; portal infiltrate