Abstract
Non-alcoholic fatty liver disease (NAFLD) is the most common, chronic liver disorder in the United States (US). Non-alcoholic steatohepatitis (NASH), the more severe form of NAFLD with hepatocyte necroinflammation that may lead to cirrhosis and hepatocellular carcinoma (HCC), is believed to be common, but its true prevalence is unclear. To bridge this knowledge gap, we aimed to estimate the prevalence of NAFLD and NASH in the US obesity and diabetes populations using the National Health and Nutrition Examination Survey (NHANES) 2015-2016 data. NAFLD was defined as a US fatty liver index (USFLI) of ≥30 (1) and NASH as a NAFLD fibrosis score (NFS) of >0.676 (2). Data were collected from 5,662 individuals, aged ≥18 years. Of these, 2,246 (39.7%) patients had obesity (body mass index [BMI] ≥30 kg/m(2)) and 869 (15.3%) had diabetes (self-reported based on physician diagnosis and/or taking diabetes medications). We observed a significant overlap between diabetes, obesity, and NAFLD. In the obese population, 62.7% of patients had NAFLD and 14.2% had NAFLD and diabetes. In the diabetes cohort, 61.2% of patients had obesity, 61.7% had NAFLD alone and 47% had obesity and NAFLD. The presence of advanced fibrosis (NFS) was high in patients with obesity (16.7%), higher in patients with diabetes (32.4%) and the highest in patients with both obesity and diabetes (37.5%). The prevalence of NAFLD was higher in patients with diabetes and worse glycemic control (i.e., 70% in patients with glycated hemoglobin [HbA1c] > 8% vs. 55% in patients with HbA1c ≤ 8%). In conclusion, patients with obesity and/or diabetes have a very high risk of NAFLD and fibrosis. Advanced fibrosis was two-fold higher in patients with diabetes vs. obese patients, making these patients a high-risk population to consider for screening. The USFLI and NFS could be useful tools to screen populations at risk for NAFLD and NASH. References: (1) Ruhl CE et al. Aliment Pharmacol Ther. 2015 Jan;41(1):65-76. (2) Le MH et al. PLoS One. 2017 March;12(3): e0173499.