Steatosis Non-Invasive Tests Accurately Predict Metabolic Dysfunction-Associated Steatotic Liver Disease, While Fibrosis Non-Invasive Tests Fall Short: Validation in U.S. Adult Population

Introduction Metabolic dysfunction associated steatotic liver disease (MASLD) has replaced NAFLD as the diagnostic standard. This study aimed to validate steatosis and fibrosis non-invasive tests (NITs) used for NAFLD in predicting MASLD and advanced fibrosis, compared to transient elastography (TE), respectively. Methods This cross-sectional study used the NHANES database (2017–2020). The Dallas steatosis index (DSI), fatty liver index (FLI), Framingham steatosis index (FSI) and hepatic steatosis index (HSI) were assessed against TE diagnosed MASLD. The NAFLD fibrosis score (NFS), fibrosis-4 (FIB-4), APRI (The aspartate aminotransferase to platelet ratio index), and BARD (body mass index, aspartate aminotransferase/alanine aminotransferase ratio diabetes score) were assessed against TE diagnosed advanced fibrosis. The diagnostic accuracy evaluated with the weighted ROC analysis. Results The study included 5,399 participants (51% female), with an estimated MASLD prevalence of 42.9%, and 10.6% indicated advanced fibrosis as assessed by TE. Steatosis NITs showed good diagnostic accuracy for predicting MASLD (AUROC 0.835 to 0.862), with FLI having the maximum Youden index (0.55). Fibrosis NITs indicated poor to fair diagnostic performance for predicting advanced fibrosis (AUROC 0.572 to 0.699) but had high NPV (89%-94%). In an age categorized subgroup analysis fibrosis NITs indicated poor performance in those aged ≤ 35 years and exhibited unacceptably low specificity to exclude fibrosis in those aged ≥ 65 years. Conclusion In this population-based cohort of U.S. adults, all steatosis NITs demonstrated good diagnostic accuracy for MASLD. However, the fibrosis NITs showed limited diagnostic ability and were influenced by age, suggesting they should be used with caution in the general population.