Non-alcoholic fatty liver disease

Abstract

Non-alcoholic fatty liver disease (NAFLD) is the most common cause of chronic liver disease worldwide. NAFLD is defined by excess fat in the liver and has a multidirectional relationship with metabolic syndrome. The prevalence of NAFLD has risen rapidly in recent years in line with the obesity epidemic and associated increases in type 2 diabetes, hypertension and hypercholesterolaemia. Patients with NAFLD are at risk of cardiovascular disease and cancer, and in a proportion of individuals, NAFLD is associated with liver damage. This article summarises the epidemiology of NAFLD, the clinical approach to risk-assessing patients and briefly outlines current and future management options.

Keywords: Non-alcoholic fatty liver disease; cirrhosis; fibrosis; non-alcoholic steatohepatitis.

Fig 1.

Non-alcoholic fatty liver disease spectrum. Approximate estimates of prevalence in the general population (black text) and rates of progression or regression (teal text and arrows). NASH = non-alcoholic steatohepatitis.

Fig 2.

Proposed algorithm for diagnosis of non-alcoholic fatty liver disease and non-invasive assessment of liver fibrosis. Adapted from Horn P, Newsome PN. NAFLD – diagnosis, assessment and management. British Society of Gastroenterology, 2020. ^a = NFS threshold <0.12 for patients >65 years; ^b = FIB-4 threshold <2.0 for patients >65 years old; ELF = enhanced liver fibrosis score; FIB-4 = Fibrosis-4 index for liver fibrosis; NAFLD = non-alcoholic fatty liver disease; NFS = NAFLD fibrosis score; NPV = negative predictive value; PPV = positive predictive value.