Prevalence and natural history of NAFLD

Nonalcoholic fatty liver disease (NAFLD) is very common, affecting an estimated 5.7 million people in Australia (including approximately 40% of adults over the age of 50 years). Adolescents and children are also at risk, and nonalcoholic fatty liver disease should be considered in obese adolescents and children. The prevalence of nonalcoholic fatty liver disease in Australia is expected to rise significantly in the coming decades.

Up to 5% of patients with nonalcoholic fatty liver disease will have advanced fibrosis. While fibrosis progression is usually slow (over many years), a subgroup of patients progresses more rapidly. With good management, fibrosis can regress over time.

In patients with pre-existing chronic liver disease, nonalcoholic fatty liver disease is an important cofactor for fibrosis progression.

The leading cause of death in patients with nonalcoholic fatty liver disease is cardiovascular disease, followed by non–liver-related malignancy. Patients with advanced liver fibrosis or cirrhosis have a higher risk of liver-related morbidity and mortality; among those with cirrhosis, up to 40% will die from liver-related disease. Patients with nonalcoholic fatty liver disease have an increased risk of comorbid conditions (gout, obstructive sleep apnoea) and may also have hyperferritinaemia.