From the Guidelines
Yes, fatty liver disease can cause elevations in liver function tests (LFTs). In fatty liver disease, the accumulation of fat in liver cells triggers inflammation and cellular damage, which leads to the release of liver enzymes into the bloodstream. Typically, patients with fatty liver disease show elevations in alanine aminotransferase (ALT) and aspartate aminotransferase (AST), with ALT usually higher than AST, as noted in a recent study 1. The elevations are often mild to moderate, typically less than five times the upper limit of normal. Other LFT abnormalities may include elevated gamma-glutamyl transferase (GGT) and alkaline phosphatase (ALP). However, bilirubin levels usually remain normal until advanced liver disease develops.
The degree of LFT elevation doesn't always correlate with the severity of fatty liver, as some patients with significant fatty infiltration may have normal or minimally elevated enzymes. Management focuses on addressing underlying causes such as alcohol cessation, weight loss, diabetes control, and treatment of dyslipidemia, which can lead to normalization of LFTs as the fatty liver improves. According to recent guidelines 1, evaluation for nonalcoholic fatty liver disease should be done at diagnosis and annually thereafter by measuring AST and ALT, and referral to gastroenterology should be considered for persistently elevated or worsening transaminases.
Key points to consider in the management of fatty liver disease include:
- Evaluation for nonalcoholic fatty liver disease by measuring AST and ALT at diagnosis and annually thereafter 1
- Referral to gastroenterology for persistently elevated or worsening transaminases 1
- Addressing underlying causes such as alcohol cessation, weight loss, diabetes control, and treatment of dyslipidemia to improve fatty liver and normalize LFTs. It is essential to prioritize the management of fatty liver disease to prevent progression to advanced liver disease and to improve patient outcomes, as supported by recent studies 1.
From the Research
Fatty Liver Disease and Liver Function Tests (LFTs)
- Fatty liver disease, specifically nonalcoholic fatty liver disease (NAFLD), is a common cause of mildly elevated liver transaminase levels 2, 3.
- Studies have shown that NAFLD can affect up to 30% of the population and is a major contributor to abnormal liver function tests (LFTs) 2, 4.
- The most common liver enzymes affected in NAFLD are alanine transaminase (ALT) and aspartate transaminase (AST) 2, 3, 4, 5, 6.
Relationship Between Fatty Liver Disease and LFTs
- Research suggests that fatty liver disease can lead to elevations in LFTs, including ALT and AST 2, 3, 4, 5, 6.
- However, the relationship between fatty liver disease and LFTs is not always straightforward, and LFTs may not always accurately reflect the severity of the disease 4.
- Factors such as illness uncertainty can also impact LFTs in patients with NAFLD, with higher illness uncertainty leading to higher ALT and AST levels 6.
Evaluation and Management of Elevated LFTs
- The evaluation of elevated LFTs should include a stepwise approach, considering the prevalence of diseases that cause mild elevations in transaminase levels 2, 3.
- Initial testing should include a fasting lipid profile, measurement of glucose, serum iron, and ferritin, and hepatitis B and C testing 2, 3.
- Further testing, such as ultrasonography and liver biopsy, may be necessary if transaminase levels remain elevated for six months or more 2 or if there is a high suspicion of advanced fibrosis or steatohepatitis 4.