What is the difference between MASLD and MASH?

Steatotic liver disease is categorized based on disease progression, ranging from fatty liver to more advanced stages involving inflammation and damage of the liver.

One example of this progression is the shift in terminology from MASLD (Metabolic dysfunction-associated steatotic liver disease) to MASH (Metabolic dysfunction-associated steatohepatitis), and more importantly, the progression from MASLD to the more severe form, MASH.

Distinguishing between MASLD and MASH is important for proper management and treatment. 
 

• MASLD: If you have excess fat in your liver driven by cardiometabolic risk factors, the disease is called metabolic dysfunction-associated steatotic liver disease². MASLD was formerly known as non-alcoholic fatty liver disease (NAFLD).  
  
  
• MASH: MASH is a more severe form of liver disease compared to MASLD. If you have excess fat in your liver driven by cardiometabolic risk factors and your liver cells have been damaged, indicating inflammation and a higher risk of complications, the disease is classified as MASH. MASH was formerly known as non-alcoholic steatohepatitis (NASH).

Neither of these diseases are related to alcohol consumption. 

Definition: MASLD refers to a range of conditions where excess fat accumulates in the liver due to cardiometabolic risk factors, that are not related to excessive alcohol consumption. 

Distinction: MASLD involves fat build-up in the liver without significant inflammation or cell damage. However, over time, MASLD can progress to the more severe form, MASH, where this build-up of excess fat can cause inflammation and may lead to more significant liver cell damage.

Symptoms: For many people MASLD is asymptomatic. However, symptoms may include abdominal pain (usually on the upper right side), back pain, fatigue, weakness, and itchy skin. These symptoms can be mistaken for other conditions, which is why regular check-ups of your liver function is recommended for people with cardiometabolic risk factors.

Diagnosis: MASLD is normally assessed through a score called FIB-4 which can be calculated based on simple standard blood tests. Further simple imaging and blood tests may follow to support the assessment of the disease severity and differentiate it from other liver conditions. This helps determine if the condition is simple steatosis or has progressed to the more advanced stage of MASH.

Treatment: Treatment options remain limited and guidance to reverse, stop or slow the progression of MASLD is to eat a healthy diet, maintain an active lifestyle, and manage any risk factors⁴.