S2419 Demographic and Metabolic Predictors of Liver Fibrosis Severity in US Adults: A NHANES 2017-2018 Transient Elastography Study

Introduction: Advanced fibrosis is the strongest prognostic marker in metabolic dysfunction–associated steatotic liver disease (MASLD), surpassing steatosis in predicting mortality, liver‐related events, and cardiovascular complications. While biopsy is the gold standard, transient elastography offers scalable fibrosis assessment, with early stiffness rises predicting adverse outcomes. To refine risk stratification, we aimed to examine population-level disparities and identify demographic and metabolic predictors of fibrosis severity in a nationally representative cohort. Methods: We analyzed 3,206 U.S. adults (≥18 years) from NHANES 2017-2018 with valid transient elastography and complete anthropometric, metabolic, and liver biochemistry data. Transient elastography fibrosis stages (none <7.0, mild 7.0–7.9, moderate 8.0–11.9, advanced ≥12.0 kPa) were first described by sex and race/ethnicity using survey weights. Among those with fibrosis (n = 846), we used multivariable ordinal logistic regression (adjusting for age, diabetes, and alcohol use) to identify demographic and metabolic predictors and applied Kruskal–Wallis tests to assess trends in body mass index (BMI), waist–hip ratio (WHR), fasting glucose, HDL, alanine aminotransferase (ALT), and FIB-4 across stages. Results: Overall, 26.4% of participants exhibited measurable fibrosis, including 7.9% with advanced fibrosis. In adjusted analyses, male sex (aOR 1.66; 95% CI, 1.41–1.96) and Non‐Hispanic Black race (aOR 1.29; 95% CI, 1.04–1.61) were significantly associated with higher odds of greater fibrosis severity. Among metabolic variables, WHR (aOR 1.23 per 0.1‐unit increase; 95% CI, 1.14–1.33) and fibrosis-4 (FIB-4) score (aOR 1.22 per unit; 95% CI, 1.10–1.35) emerged as the strongest independent predictors, followed by ALT (aOR 1.06 per 10 U/L; 95% CI, 1.03–1.09) and BMI (aOR 1.06 per kg/m²; 95% CI, 1.03–1.08). Kruskal–Wallis testing confirmed significant, stepwise increases across fibrosis stages for WHR, FIB‐4 score, BMI, glucose, HDL, and ALT; all P < 0.001. Conclusion: In this nationally representative U.S. cohort, male sex, Non‐Hispanic Black race, and central adiposity independently predicted more severe liver fibrosis measured by transient elastography. WHR, FIB‐4 score, BMI, and ALT offered the greatest discriminatory power across fibrosis stages. These findings not only highlighted risk factors for more severe fibrosis but also support the need for longitudinal validation to refine population‐level risk algorithms for liver fibrosis.