What is the most common cause of elevated Aspartate Aminotransferase (AST) and Alanine Aminotransferase (ALT)?

From the Guidelines

The most common cause of elevated AST and ALT is non-alcoholic fatty liver disease (NAFLD), which affects approximately 20-30% of the general population, as stated in the study by 1. This condition is characterized by the accumulation of fat in liver cells, leading to inflammation and damage. Other common causes of elevated liver enzymes include alcoholic liver disease, viral hepatitis, and medication-induced liver injury. The study by 1 highlights that NAFLD is a spectrum of fat deposition and hepatic inflammation, followed by fibrosis due to metabolic insults, and it is the most common liver disease in first-world countries. Key points to consider when evaluating elevated AST and ALT include:

• The pattern of elevation, with ALT being more specific to liver damage, while AST can also be elevated in muscle disorders, heart conditions, or kidney disease, as noted in the study by 1.
• The severity of abnormal aminotransferase, which can be classified as mild, moderate, or severe, with moderate and severe elevations warranting further investigation, as discussed in the study by 1.
• The importance of lifestyle modifications, such as weight loss and avoiding alcohol, in managing elevated liver enzymes, as well as treating underlying conditions, such as discontinuing potentially hepatotoxic medications. Overall, the management of elevated AST and ALT should prioritize addressing the underlying cause, with further investigation and treatment guided by the severity and pattern of elevation, as recommended by the study by 1.

From the Research

Causes of Elevated AST and ALT

• The most common causes of elevated aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are related to liver diseases, including hepatitis C and non-alcoholic fatty liver disease (NAFLD) 2, 3, 4, 5.
• Hepatitis C, especially genotype 3, is often associated with hepatic steatosis, which can lead to elevated AST and ALT levels 3, 5.
• NAFLD is also a common cause of elevated AST and ALT, and is often associated with metabolic syndrome, insulin resistance, and hepatic steatosis 2, 4, 5.
• The presence of NAFLD in patients with hepatitis C genotype 1 infection is most strongly associated with the presence of metabolic syndrome and insulin resistance 3.
• The degree of hepatic steatosis correlates with the degree of hepatic fibrosis, and the presence of concomitant steatosis is associated with more advanced fibrosis 3, 5.

Relationship between Hepatitis C and NAFLD

• There is a significant overlap between hepatitis C and NAFLD, and the relationship between the two diseases appears to go beyond isolated co-existence 2, 3, 5.
• Hepatic steatosis is a common feature of chronic hepatitis C (CHC) infection and can be related to both metabolic and viral specific factors 2, 5.
• The presence of NAFLD in patients with hepatitis C can affect the response to antiviral therapy, and the management of obesity and metabolic syndrome may be important for reducing the risk of progression and improving the efficacy of antiviral therapy 5.