Mortality in metabolic dysfunction-associated steatotic liver disease: A nationwide population-based cohort study

Background: A new fatty liver disease nomenclature, steatotic liver disease (SLD) has been proposed; however, there are no data on clinical outcomes. We investigated the impact of SLD with metabolic dysfunction (MD; SLD-MD) on all-cause mortality. Methods: We evaluated nationally representative participants aged ≥19 years using data from the Korea National Health and Nutrition Examination Survey 2007–2015 and their linked death data through 2019. The presence of fatty liver disease was assessed by liver fat score, fatty liver index and significant liver fibrosis was evaluated by the Fibrosis-4 Index, and fibrosis score. SLD-MD was categorized into three groups: metabolic dysfunction-associated steatotic liver disease (MASLD); metabolic alcoholic liver disease (MetALD); and SLD with other combination etiologies. Results: Among 26734 individuals (11561 men and 15173 women, mean age 48.8 years), 1833 (6.9 %) died during a mean follow-up period of 110.6 ± 33.9 months. Mortality risk was significantly higher in individuals with SLD-MD (hazard ratio [HR] = 1.35) than in those without (P < 0.001). Among the three groups, MASLD (HR = 1.32) and SLD with other combination etiologies (HR = 2.06) independently increased mortality risk (all P < 0.001). When individuals with SLD-MD had significant liver fibrosis or diabetes, mortality risk increased further (HR = 1.68 and 1.85, respectively; all P < 0.001). SLD-MD with both significant liver fibrosis and diabetes showed the highest mortality risk (HR = 2.29, P < 0.001). When applied fatty liver index and fibrosis score, similar results were observed. Conclusions: SLD-MD is associated with a higher mortality risk. When SLD-MD was combined with significant liver fibrosis or diabetes, the mortality risk became much higher. Treatment strategies to reduce fibrotic burden and improve glycemic control in individuals with MASLD are needed.