Trends of chronic liver diseases by income level and socioeconomic factors in the United States: A population-based study

Background/Aims: With polarizing income disparities, this study investigated the prevalence and trends of liver disease in a U.S. population-based sample based on income-to-poverty ratio (IPR). Methods: This cross-sectional study analysed survey data from the 1999-2018 National Health and Nutrition Examination Survey with highest (HIG), middle-income (MIG), and lowest income (LIG) groups defined as IPR <= 1, 1 < IPR <5, and IPR >= 5, respectively. Results: We analysed 59,204 adult participants with 48.2% male, 39.7% aged 18-39, 36.2% 40-59, and 24.1% >= 60 years. The weighted prevalence of hepatitis C (HCV), B (HBV) infection, non-alcoholic fatty liver disease (NAFLD), alcohol-associated liver disease (ALD), and advanced fibrosis in LIG were 3.9% (n = 276), 7.4% (n = 527), 33.2% (n = 714), 5.2% (n = 401), and 9.0% (n = 694), respectively, compared to lower rates for HIG: 1.0% (n = 82), 3.2% (n = 263), 29.6% (n = 798), 3.9% (n = 354), and 5.0% (n = 638). After adjusting for age, sex, race and ethnicity, education, and birthplace, HIG had the lowest odds of having any liver disease [adjusted odds ratio (aOR) 0.67, p < 0.0001], with similar findings for specific conditions including HCV, HBV, and advanced fibrosis (aOR 0.24, 0.52, and 0.64, all p < 0.0001, respectively). While viraemic HCV prevalence decreased over time for HIG, there were no changes for MIG nor LIG. Similarly, NAFLD prevalence was stable for HIG but increased for MIG and LIG. Conclusion: LIG and MIG in the United States have higher liver disease burdens than HIG, with increasing NAFLD prevalence and lack of decline in current HCV infection prevalence over time as opposed to declining or stable trend in HIG.