Abstract
OBJECTIVES: The global burden of non-alcoholic fatty liver disease (NAFLD) is rising. An alternative term, metabolic dysfunction-associated fatty liver disease (MAFLD), instead highlights the associated metabolic risks. This cohort study examined patient classifications under NAFLD and MAFLD criteria and their associations with all-cause mortality. METHODS: Participants who attended a paid health check-up (2012-2015) were included. Hepatic steatosis (HS) was diagnosed ultrasonographically. NAFLD was defined as HS without secondary causes, while MAFLD involved HS with overweight/obesity, type 2 diabetes mellitus, or ≥2 metabolic dysfunctions. Mortality was tracked via the Taiwan Death Registry until November 30, 2022. RESULTS: Of 118,915 participants, 36.9% had NAFLD, 40.2% had MAFLD, and 32.9% met both definitions. Participants with NAFLD alone had lower mortality, and those with MAFLD alone had higher mortality, than individuals with both conditions. After adjustment for potential confounders, the hazard ratios (HRs) for all-cause mortality were 1.08 (95% confidence interval [CI], 0.78 to 1.48) for NAFLD alone and 1.26 (95% CI, 1.09 to 1.47) for MAFLD alone, relative to both conditions. Advanced fibrosis conferred greater mortality risk, with HRs of 1.93 (95% CI, 1.44 to 2.58) and 2.08 (95% CI, 1.61 to 2.70) for advanced fibrotic NAFLD and MAFLD, respectively. Key mortality risk factors for NAFLD and MAFLD included older age, unmarried status, higher body mass index, smoking, diabetes mellitus, chronic kidney disease, and advanced fibrosis. CONCLUSIONS: All-cause mortality in NAFLD and/or MAFLD was linked to cardiometabolic covariates, with risk attenuated after multivariable adjustment. A high fibrosis-4 index score, indicating fibrosis, could identify fatty liver disease cases involving elevated mortality risk.