Prevalence of High and Moderate Risk Nonalcoholic Fatty Liver Disease Among Adults in the United States, 1999-2016.

BACKGROUND AND AIMS: Nonalcoholic fatty liver disease (NAFLD) subjects with fibrosis stage ≥2 are at high risk for mortality. We aimed to provide national estimates and temporal trends for NAFLD, based on different fibrosis severity. METHODS: Data from the National Health and Nutrition Examination Survey (NHANES) (1999-2016) and NHANES III (1988-1994) were utilized. NAFLD was determined by ultrasound showing moderate to severe steatosis. For those without ultrasound, NAFLD was determined by the U.S. Fatty Liver Index score of ≥30. Hepatic fibrosis was assessed using Fibrosis-4 (FIB-4) score (FIB-4 <1.3 = low risk; FIB-4 1.3-2.67 = moderate risk; and FIB-4 >2.67 = high risk). Annual percent change (APC) was calculated by using the joinpoint regression model. RESULTS: From NHANES III, 10,854 individuals were included (mean age 43.5 years; 47.5% male; 75.7% non-Hispanic White) and 37.7% had NAFLD. Among them, based on FIB-4, 80% had low-risk, 18.6% had moderate-risk, and 1.4% had high-risk NAFLD. NAFLD with moderate or high risk was more likely to have hypertension, hyperlipidemia, diabetes, cardiovascular disease, and metabolic syndrome than was low-risk NAFLD (all P < .02). NAFLD prevalence increased from 29.5% in 1999-2000 to 40.3% in 2015-2016 (APC, 2.78%; P < .02), moderate-risk NAFLD increased from 6.26% to 14.17% (APC, 5.34%; P < .02), and high-risk NAFLD increased from 0.49% to 1.15% (APC, 9.72%; P < .02). Independent predictors of advanced fibrosis were age (OR, 1.11; 95% CI, 1.06-1.17; P = .001) and diabetes (OR, 2.28; 95% CI, 1.03-5.05; P = .04). Compared with low-risk NAFLD, high-risk NAFLD was associated with significantly increased all-cause (HR, 1.53; 95% CI, 1.09-2.15; P = .01), cardiovascular disease-specific (HR, 1.99; 95% CI, 1.22-3.24, P < .01) and liver-specific (HR, 4.57; 95% CI, 1.03-28.79; P = .04) mortality. CONCLUSIONS: The prevalence of moderate- or high-risk NAFLD is increasing and is associated with increased all-cause, liver-related, and cardiovascular mortality.