Metabolic dysfunction-associated steatotic liver disease (MASLD), also known as nonalcoholic fatty liver disease (NAFLD), is the most common liver disease around the world (prevalence of 25%), with 30% of the US population affected. MASLD is a chronic condition of fat accumulation in the liver without involvement of excessive alcohol consumption or use of steatogenic medications. MASLD represents a spectrum of disease, from steatotic liver disease (SLD) (steatosis without hepatocellular injury; also known as nonalcoholic fatty liver [NAFL]) to metabolic dysfunction-associated steatohepatitis (MASH) (steatosis with hepatic injury / inflammation; also known as nonalcoholic steatohepatitis [NASH]) to progressive fibrosis and liver cirrhosis. SLD encompasses MASLD and MetALD, a term describing people with MASLD who consume more than 140 g of alcohol per week for women and 210 g per week for men. MetALD accounts for the continuum of disease between MASLD and alcohol-related liver disease (ALD). With advancements in the treatment of viral hepatitis and a continual increase in obesity and metabolic syndrome in the United States, MASLD is becoming one of the most common causes of cirrhosis in the United States. With cirrhosis comes an increased risk of developing hepatocellular carcinoma.

Screening for MASLD is of the utmost importance in patients with underlying risk factors, primarily obesity and metabolic syndrome, as it is often asymptomatic. Some patients report vague symptoms such as fatigue or mild right upper quadrant abdominal pain. If MASLD progresses to cirrhosis, patients will often present with signs and symptoms of advanced liver disease: spider angiomata, gynecomastia, ascites, jaundice, and peripheral edema.

The primary risk factors for MASLD are central obesity, type 2 diabetes mellitus, and hyperlipidemia. Modification of these risk factors, mostly through weight loss and dietary and lifestyle changes, is the most effective preventive and treatment strategy.