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.

FIGURE 1

Estimated National Prevalence of Steatotic Liver Disease and subclassifications. Estimated national prevalence of SLD, MASLD, MetALD, ALD, and specific etiology or cryptogenic SLD with 95% CIs using CAP of ≥ 288 dB (A) or ≥ 248 dB (B) to define presence of liver steatosis. Abbreviations: ALD, alcohol-associated liver disease; CAP, controlled attenuation parameter; MASLD, metabolic dysfunction-associated steatotic liver disease; MetALD, metabolic dysfunction-associated steatotic liver disease and increased alcohol intake; SLD, steatotic liver disease.

FIGURE 2

Estimated National Prevalence of Steatotic Liver Disease and subclassifications by key subgroups. Estimated national prevalence of SLD, MASLD, and MetALD with 95% CIs, among adults with age below 45 vs. 45 or above (A), men versus women (B), by race/ethnicity (non-Hispanic White, non-Hispanic Black, Asian, Hispanic, and Other) (C), without versus with advanced liver fibrosis as determined by vibration-controlled transient elastography (LSM <11.7 vs. ≥ 11.7 kPa) (D). ALD and specific etiology or cryptogenic SLD are not presented by key subgroups due to small sample sizes. Abbreviations: LSM, liver stiffness measurement; MASLD, metabolic dysfunction-associated steatotic liver disease; MetALD, metabolic dysfunction-associated steatotic liver disease and increased alcohol intake; SLD, steatotic liver disease.

FIGURE 3

Overlap between NAFLD and MASLD. Among those with NAFLD or MASLD, 99.0% (95% CI 97.6%–99.6%) met the criteria for both NAFLD and MASLD. The MASLD criteria were not met 0.1% (95% CI 0.05%–0.28%) reflecting a small subgroup with NAFLD but lacking metabolic risk factors. Another 0.9% (95% CI 0.3%–2.3%) only met the MASLD criteria reflecting a small subgroup with viral hepatitis not captured by NAFLD. Abbreviation: MASLD, metabolic dysfunction-associated steatotic liver disease.