Significant burden of nonalcoholic fatty liver disease with advanced fibrosis in the US: a cross-sectional analysis of 2011-2014 National Health and Nutrition Examination Survey

Background: Nonalcoholic fatty liver disease (NAFLD) is a leading cause of chronic liver disease in the US. Understanding the epidemiology of NAFLD, with specific focus on individuals with hepatic fibrosis is important to guide healthcare resource planning. Aim: To evaluate prevalence and predictors of hepatic fibrosis among US adults with NAFLD. Methods: We performed a cross-sectional study using data from the updated 2011-2014 National Health and Nutrition Examination Survey, a national, stratified, multistage sampling survey of non-institutionalised US adults age >= 20. METAVIR F2 or greater fibrosis among individuals with NAFLD was assessed using AST to Platelet Ratio Index (APRI) score > 0.7. METAVIR F3 or greater fibrosis was assessed using NAFLD fibrosis score (NFS) > 0.676 and FIB-4 score > 3.25. Multivariate logistic regression models evaluated for predictors of fibrosis among individuals with NAFLD. Results: Overall prevalence of NAFLD among US adults was 21.9% (95% CI 20.6-23.3), representing 51.6 million adults. Among individuals with NAFLD, we observed a 23.8% prevalence of >= F2 fibrosis, representing 12.2 million individuals, and we observed a 2.3%-9.7% prevalence of >= F3 fibrosis, representing as many as 5.0 million adults. On multivariate regression analyses, increasing age, obesity and concurrent diabetes mellitus were associated with increased risk of >= F3 fibrosis. Conclusions: NAFLD represents a major healthcare burden among US adults with as many as 5 million adults estimated to have NAFLD with >= F3 fibrosis. Age and the components of the metabolic syndrome are independently associated with higher risk of fibrosis.