Metabolic dysfunction-associated steatotic liver disease (MASLD)

🧭 When to suspect

Metabolic dysfunction-associated steatotic liver disease (MASLD) describes hepatic steatosis in the absence of harmful alcohol use or another identifiable cause. It is the commonest liver disorder in the UK, affecting roughly a quarter to a third of adults, and is best understood as the hepatic manifestation of the metabolic syndrome. NICE adopted the new terminology when it renamed and updated guideline NG49 in July 2026, with a fuller content update still in development.

Most patients are asymptomatic, the condition usually surfacing incidentally as abnormal liver blood tests or a “bright” or echogenic liver reported on ultrasound requested for another reason. A critical point for primary care: routine liver function tests cannot rule it out – ALT is normal in roughly half of those with MASLD, including some with advanced fibrosis.

The disease spectrum runs steatosis → steatohepatitis → fibrosis → cirrhosis, but it is the fibrosis stage, not the amount of fat or the ALT level, that determines prognosis. Only a small minority progress to cirrhosis, and for most the dominant threat is cardiovascular rather than hepatic. The task is therefore twofold: case-find in those with cardiometabolic risk – particularly type 2 diabetes, obesity and the metabolic syndrome – and risk-stratify for fibrosis, rather than simply reassure on a normal liver edge or a normal ALT.

Source: NICE NG49 · British Society of Gastroenterology