Nonalcoholic fatty liver disease (NAFLD) is the most common liver disease in the Western countries, affecting 20-40% of adults. NAFLD is increasingly a cause of cirrhosis and hepatocellular carcinoma globally. This burden is expected to increase as the epidemics of obesity, type 2 diabetes and metabolic syndrome continue to grow.
NAFLD includes nonalcoholic fatty liver (NAFL) and nonalcoholic steatohepatitis (NASH). NAFL is generally benign whereas NASH can progress to liver cirrhosis, liver failure or hepatocellular carcinoma.
For the diagnosis of NAFLD, it is required that liver steatosis is confirmed by ultrasound or histology, there is no significant alcohol consumption and there are no competing etiologies for chronic liver disease. Patients with elevated liver tests should be assessed for metabolic risk factors (e.g. obesity, type 2 diabetes mellitus, dyslipidemia) and other causes such as alcohol consumption or medication use. Ultrasound is the preferred first-line diagnostic procedure for imaging NAFLD. The definitive diagnosis of NASH requires taking a liver biopsy, which should be considered in the case of patients who are at an increased risk of advanced fibrosis. Fibrosis is the most important prognostic factor for NASH and is correlated with liver-related outcomes. The best validated non-invasive fibrosis serum markers are NAFLD fibrosis score (NFS-score), enhanced liver fibrosis panel (ELF-panel) and fibrosis 4 calculator (FIB-4).
Patients with NAFLD cirrhosis should be screened for gastroesophageal varices and hepatocellular carcinoma similarly to all cirrhosis patients.