National prevalence estimates for steatotic liver disease and subclassifications using consensus nomenclature

Abstract

Background and aims: The multisociety consensus nomenclature has renamed NAFLD to steatotic liver disease (SLD) with various subclassifications. There is a paucity of data regarding how the new nomenclature modifies our understanding of disease prevalence and patient phenotypes.

Approach and results: Using the National Health and Nutrition Examination Survey from January 2017 to March 2020, we included all participants aged 18 years or above with complete vibration-controlled transient elastography measures. SLD and its subclassifications [metabolic dysfunction-associated SLD (MASLD), MASLD + increased alcohol intake (MetALD), alcohol-associated liver disease (ALD), etiology-specific/cryptogenic] were defined according to consensus nomenclature. National SLD prevalence and subclassifications were estimated, and among key subgroups [age, sex, race/ethnicity, advanced liver fibrosis (liver stiffness measurement [LSM] ≥11.7 kPa)]. Among 7367 participants, 2549 had SLD (mean age 51 y, 57.7% male, 63.2% non-Hispanic White). The estimated prevalence of SLD was 34.2% (95% CI 31.9%-36.5%): MASLD 31.3% (29.2%-33.4%), MetALD 2% (1.6%-2.9%), ALD 0.7% (0.5-0.9%), etiology-specific/cryptogenic 0.03% (0.01%-0.08%). In exploratory analyses, participants classified as non-SLD with (vs. without) advanced fibrosis had a higher mean number of metabolic risk factors [2.7 (2.3-3.1) vs. 2.0 (1.9-2.0)] and a higher proportion with average alcohol use ≥20 g/d (women)/≥30 g/d (men) [20.9% (6.2%-51.3%) vs. 7.2% (6.1%-8.4%)]. In another exploratory analysis, increasing quantities of alcohol use remaining below the threshold for MASLD + increased alcohol intake were associated with advanced liver fibrosis in men, but not women. There was 99% overlap in cases of NAFLD and MASLD.

Conclusions: Our findings highlight the utility of the new consensus nomenclature to address deficiencies present with the old nomenclature, and identify areas that require research to further refine classifications of SLD.