Metabolic dysfunction-associated steatohepatitis is associated with increased all-cause mortality

Abstract

Background: Recently, the new nomenclature metabolic dysfunction-associated steatohepatitis (MASH) was proposed to supersede non-alcoholic steatohepatitis (NASH). To optimize the management of these patients, it is crucial to comprehend the similarities and differences between individuals with NASH and MASH. Methods: We analyzed data from 13,846 participants in the third National Health and Nutrition Examination Surveys, along with their linked mortality through 2019. NASH and MASH were defined based on respective criteria. Survey-weight adjusted multivariable Cox proportional model was used to examine mortality. Results: The overall prevalence of steatohepatitis, NASH and MASH was 5.7% (n=788), 4.1% (n=564) and 5.5% (n=763), respectively. Most individuals with NASH (96.8%) could be categorized as MASH, but only 69.7% individuals with MASH qualified as NASH. During a median follow-up of 27 years, individuals with MASH exhibited a 53% higher risk of all-cause mortality (adjusted hazard ratio [aHR] 1.53, 95% CI 1.24-1.89). But individuals with NASH did not show an association with all-cause mortality after adjustment for metabolic risk factors (aHR 1.14, 95% CI 0.91-1.44). Notably, individuals who met the criteria for MASH but not NASH (NASH(-)/MASH(+)) had a higher risk of all-cause mortality (aHR 2.47, 95% CI 1.71-3.57) compared to those with NASH(+)/MASH(+) (aHR 1.22, 95% CI 0.97-1.55). Moreover, advanced fibrosis was only associated with an increased risk of all-cause mortality in individuals with MASH, not NASH. Conclusions: MASH, rather than NASH, was associated with an elevated risk of all-cause mortality after adjusting for metabolic risk factors. Well-designed prospective studies are needed to assess and validate our findings.