The clinical and public health significance of nonalcoholic fatty liver disease (NAFLD) is not well established. We investigated the long-term effect of NAFLD on mortality. This analysis utilized the National Health and Nutrition Examination Survey conducted in 1988-1994 and subsequent follow-up data for mortality through December 31, 2006. NAFLD was defined by ultrasonographic detection of hepatic steatosis in the absence of other known liver diseases. The presence and severity of hepatic fibrosis in subjects with NAFLD was determined by the NAFLD fibrosis score (NFS), the aspartate aminotransferase to platelet ratio index (APRI), and FIB-4 score. Of 11,154 participants, 34.0% had NAFLD—the majority (71.7%) had NFS consistent with lack of significant fibrosis (NFS <−1.455), whereas 3.2% had a score indicative of advanced fibrosis (NFS >0.676). After a median follow-up of 14.5 years, NAFLD was not associated with higher mortality (age- and sex-adjusted hazard ratio [HR]: 1.05; 95% confidence interval [CI]: 0.93-1.19). In contrast, there was a progressive increase in mortality with advancing fibrosis scores. Compared to subjects without fibrosis, those with a high probability of advanced fibrosis had a 69% increase in mortality (for NFS: HR, 1.69, 95% CI: 1.09-2.63; for APRI: HR, 1.85, 95% CI: 1.02-3.37; for FIB-4: HR, 1.66, 95% CI: 0.98-2.82) after adjustment for other known predictors of mortality. These increases in mortality were almost entirely from cardiovascular causes (for NFS: HR, 3.46, 95% CI: 1.91-6.25; for APRI: HR, 2.53, 95% CI: 1.33-4.83; for FIB-4: HR, 2.68, 95% CI: 1.44-4.99). Conclusions : Ultrasonography-diagnosed NAFLD is not associated with increased mortality. However, advanced fibrosis, as determined by noninvasive fibrosis marker panels, is a significant predictor of mortality, mainly from cardiovascular causes, independent of other known factors.

Clinical epidemiology and disease burden of nonalcoholic fatty liver disease

Introduction Hepatocellular carcinoma (HCC) is the sixth most common cancer and the third-leading cause of cancer-related mortality in the world. Areas covered This review will discuss risk factors, demographic differences, global trends, and the economic burden of HCC. Viral hepatitis, particularly hepatitis B virus (HBV) infection, is the most common underlying liver disease leading to HCC in those with cirrhosis. Other important risk factors include alcoholic liver disease, nonalcoholic fatty liver disease, metabolic syndrome, etc. With the introduction of direct-acting antiviral agents for hepatitis C virus infection, routine vaccination against HBV, and increasing support for robust public screening programs, the incidence rates for HCC due to viral hepatitis is falling in many countries. Meanwhile, the prevalence of obesity and metabolic syndrome are on the rise, as is NAFLD-related HCC incidence. Asia and Africa have the highest incidence rates of HCC. In multiethnic countries, racial and ethnic minorities experience disparities in HCC incidence as well as mortality, representing an essential area for improvement in terms of healthcare inequity. Expert opinion Interventions to minimize the global burden of HCC aim to reduce rates of the most common risk factors and implement effective treatment of underlying etiology and comprehensive screening programs for HCC.