Comparison of the identification and practicability of non-invasive diagnostic indicators under NAFLD, MAFLD and MASLD in China: a cross-sectional study

OBJECTIVES: Early screening of non-alcoholic fatty liver disease (NAFLD) is critical for early diagnosis and management. The disease was renamed and its diagnostic criteria revised as metabolic-associated FLD (MAFLD) in 2020 and further updated to metabolic dysfunction-associated steatotic liver disease (MASLD) in 2023. This study evaluated the predictive performance and clinical feasibility of non-invasive diagnostic indicators across the NAFLD, MAFLD and MASLD diagnostic criteria. DESIGN: Cross-sectional study. SETTING: Health Management Centre in China. PARTICIPANTS: A total of 5810 participants aged ≥18 years were enrolled. Individuals with missing laboratory data, imaging results or self-reported information were excluded. PRIMARY AND SECONDARY OUTCOME MEASURES: Disease-specific indicators included Fatty Liver Index (FLI), Hepatic Steatosis Index and Zhejiang University index (ZJU). Non-disease-specific indicators included lipid accumulation product (LAP), Visceral Adiposity Index and the Triglyceride and Glucose Index. Subgroup analysis was performed by gender and Body Mass Index (BMI). RESULTS: The area under the receiver operating characteristic curve (AUROC) for all six non-invasive indicators exceeded 0.7. FLI showed the optimal predictive performance across the three criteria (NAFLD-AUROC: 0.802, MAFLD-AUROC: 0.847 and MASLD-AUROC: 0.811), with comparable performance observed for ZJU (0.797, 0.838 and 0.809, respectively). Pairwise z-tests demonstrated a significant difference between FLI and ZJU for MAFLD (p<0.05), but not for NAFLD or MASLD (all p>0.05). Subgroup analyses revealed that ZJU performed better in males (NAFLD-AUROC: 0.790, MAFLD-AUROC: 0.839 and MASLD-AUROC: 0.803), while FLI was superior in females (NAFLD-AUROC: 0.832, MAFLD-AUROC: 0.838 and MASLD-AUROC: 0.838) and in participants who were overweight (NAFLD-AUROC: 0.709, MAFLD-AUROC: 0.765 and MASLD-AUROC: 0.709). LAP exhibited the highest predictive efficacy in the normal BMI subgroup (NAFLD-AUROC: 0.758, MAFLD-AUROC: 0.804 and MASLD-AUROC: 0.796). CONCLUSIONS: FLI exhibited the highest predictive efficacy across all diagnostic criteria, and ZJU showed comparable performance. Considering diagnostic accuracy and clinical practicality, ZJU is recommended as a favourable, non-invasive tool for population-based screening in the Chinese population.