Prevalence of at-risk NASH and its association with metabolic syndrome in US adults with NAFLD, 2017–2018

Patients with metabolic syndrome (MetS) have a higher risk for NASH and significant fibrosis. Presence of NASH and advanced fibrosis are associated with adverse outcomes in patients with NAFLD. Using a noninvasive method, we determined the prevalence of at-risk NASH and its association with MetS components in a large population-based analysis. We used the 2017–2018 National Health and Nutrition Examination Survey and included adults ≥18 years with NAFLD (controlled attenuation parameter ≥274 dB/m). Pregnancy, subjects with other causes of liver disease or missing data were excluded. FibroScan-AST (FAST) score was calculated using aspartate aminotransferase, liver stiffness measurement, and controlled attenuation parameter. Patients with a FAST score >0.35 were considered to have at-risk NASH, defined as NASH with NAFLD activity score ≥4 and fibrosis stage ≥2 on liver biopsy. The sample included 687 patients. The overall prevalence of at-risk NASH was 11.6% (95% CI: 8.8–15.1) and was higher in males than females (15.8% vs. 6.5%; p < 0.001). Subjects with comorbidities (diabetes mellitus, obesity, MetS, and insulin resistance) had between 1.3 and 1.7 times higher prevalence than the general population. Among MetS components, elevated glucose/diabetes, large waist circumference, and low HDL were independent risk factors for at risk-NASH. The number of MetS components was also important—one additional component increased the odds of at-risk NASH by 2 times. The FAST score had the highest correlation with alanine aminotransferase (r= 0.70; p < 0.001). We estimated ~9 million people in the US have at-risk NASH and may benefit from active surveillance and therapy.