Clinical features and mortality outcomes of patients with MASLD only compared to those with MAFLD and MASLD.

Background and aims: The applicability of the proposed metabolic dysfunction-associated steatotic liver disease (MASLD) definition has not been validated. We aimed to characterize the profiles and long-term survival of people meeting the criteria for MASLD, but not that of metabolic dysfunction-associated fatty liver disease (MAFLD), i.e. MASLD only.

Methods: Using data from the Third National Health and Nutrition Examination Survey (NHANES III) 1988-1994, 7791 adult participants were included and categorized into four distinct groups: no SLD, non-MAFLD MASLD, MASLD-MAFLD, and cryptogenic SLD (steatosis without metabolic dysfunction).

Results: Participants in the MASLD-only group were younger and had better metabolic profiles and fibrosis degree compared to those with MASLD-MAFLD and those with no SLD. Their profiles were comparable to those with cryptogenic SLD. Similarly, the MASLD-only group tend to have lower cumulative incidence of all-cause and cardiovascular mortality. Clustering analysis showed that MASLD only clusters differently from individuals with MASLD-MAFLD.

Conclusions: MASLD only is a distinct clinical group with substantial heterogeneity compared to those captured using the MAFLD criteria.