Progression and Natural History of Nonalcoholic Fatty Liver Disease in Adults

Liver-related mortality is the third cause of death in patients with nonalcoholic fatty liver disease (NAFLD) and is significantly higher in patients with nonalcoholic steatohepatitis (NASH) compared with patients with simple steatosis (7.3% vs 0.9% respectively) within the first 15 years of follow-up. The presence and severity of fibrosis on liver biopsy is currently the best indicator of longterm liver outcomes in patients with NAFLD. The rate of fibrosis progression is at around 1 stage every 6 to 15 years in patients with NASH but is reduced by half in patients with simple steatosis; however some patients with NAFLD, also with simple steatosis, can progress rapidly to clinically significant fibrosis. Patients with NAFLD with cirrhosis have lower rates of liver-related complications but similar overall mortality as compared with patients with hepatitis C virus because of a higher incidence of cardiovascular events. Hepatocellular carcinoma incidence is growing in patients with NAFLD with or without cirrhosis, particularly among those with multiple metabolic risk factors.