Non-alcoholic fatty liver disease

Summary points

• Non-alcoholic fatty liver disease (NAFLD) represents a spectrum of liver disease with key stages consisting of hepatic steatosis (NAFL), steatohepatitis (NASH), fibrosis, and eventual cirrhosis

• NAFLD affects more than 20% of populations worldwide and most patients with type 2 diabetes mellitus

• The risk of progressive liver disease in the earliest stage of NAFLD, hepatic steatosis, is low but patients with NASH are at far higher risk, and hepatic steatosis due to NAFLD is also a major risk factor for the development of type 2 diabetes

• Most patients with NAFLD are asymptomatic and the disease is typically suspected based on raised alanine aminotransferase (ALT) levels together with other clinical and biochemical features, or an incidental finding during abdominal ultrasonography

• Owing to the slow progression of NAFLD, randomised clinical trials have been unable to identify drugs that conclusively reduce progression to cirrhosis, but sustained weight loss has been shown to improve liver function test results and liver histology and thus lifestyle improvement remains the key intervention

• There is no convincing evidence that NAFLD independently increases a patient’s cardiovascular risk but there is also no reason to withhold statins in patients with NAFLD who are at high cardiovascular risk unless transaminase levels are more than three times the upper limit of normal