Comparison of NAFLD, MAFLD, MASLD and pure-MASLD characteristics and mortality outcomes in United States adults

BackgroundAfter metabolic dysfunction-associated fatty liver disease (MAFLD), non-alcoholic fatty liver disease (NAFLD) has recently been redefined again as metabolic dysfunction-associated steatotic liver disease (MASLD). However, the distinctions in characteristics and mortality outcomes between NAFLD, MAFLD, MASLD, and pure-MASLD are still unclear. MethodsWe analyzed data from 6,708 participants in the third National Health and Nutrition Examination Surveys 1988-1994 of United States (US) and their linked mortality through 2019. NAFLD, MAFLD, MASLD and pure MASLD were defined based on respective criteria. Survey-weight adjusted multivariable Cox proportional model was used to study the mortality of the four terms. ResultsThe overall prevalence of NAFLD, MAFLD, MASLD and pure-MASLD was 28.9% (n=1,937), 26.1% (n=1,753), 29.0% (n=1,948), and 26.0% (n=1,741), respectively. For NAFLD, 81.3%, 89.9% and 89.9% fulfilled the criteria for MAFLD, MASLD and pure MASLD. For MAFLD, all were classified into the MASLD, and 89.8% were met the criteria of pure-MASLD. During a median follow-up of 27 years, both individuals with MAFLD and MASLD had higher risk of all-cause mortality (adjusted hazard ratio [aHR]: 1.21, 95% CI 1.09-1.352; and 1.11, 1.00-1.23, respectively). NAFLD and pure-MASLD were not associated with all-cause mortality. All the four terms were associated with increased all-cause mortality in individuals with advanced fibrosis (aHR: 1.66-1.83). Subgroup analyses showed that higher risk of all-cause mortality of NAFLD, MAFLD, MASLD and pure-MASLD were observed in female, age 41-55 years, non-Hispanic white, and never smoking subgroups when focused on moderate-severe hepatic steatosis. ConclusionsIn this US population-based study, MASLD could identify more individuals with all-cause mortality risk than MAFLD, meanwhile, NAFLD and pure-MASLD had similar characteristics and mortality outcomes.