摘要
Nonalcoholic fatty liver disease(NAFLD)is the most prevalent cause of chronic liver disease worldwide.In most individuals with NAFLD,liver histology is typically characterized by nonalcoholic fatty liver(NAFL),while up to 20%are noted to have nonalcoholic steatohepatitis(NASH)with or without fibrosis.The stage of NAFLD-related hepatic fibrosis and not the presence of NASH is associated with the risk of all-cause and cause-specific mortality(1,2).During the recent decade,NAFLD-associated advanced fibrosis increased in prevalence in the United States(US)from 3%among individuals with NAFLD in 2005-2008 to 6%in 2013-2016,estimated to be four million US adults(3).Notably,mortality for NAFLD-associated cirrhosis increased significantly between 2007 and 2016,with an annual increase of 15.4%(4).Although earlier studies showed that NAFLD was associated with higher mortality than the general population of the same age and sex(5),it is not clear whether more severe NAFLD is associated with the underlying metabolic complications responsible for the increased risk of all-cause and cause-specific mortalities.A US population-based study with 15 years of follow-up reported that NAFLD by itself did not increase the risk of mortality,whereas NAFLD with advanced fibrosis was associated with an increase in all-cause and cardiovascular mortality(2).After adjustment for multiple clinical and metabolic confounders beyond age and sex,NAFLD was no longer predictive of all-cause mortalities(2).A recent meta-analysis validated that the risk of all-cause and liver-related mortality increases with an increase in fibrosis stage in individuals with NAFLD(1).
