Prevalence of Elevated ALT Levels in Patients with Graves' Disease
Approximately 26-45.8% of patients with Graves' disease have elevated ALT liver levels. 1, 2, 3
Prevalence of Liver Function Abnormalities in Graves' Disease
The prevalence of liver function abnormalities in Graves' disease is significant:
- Overall hepatic dysfunction: 65-77.9% of patients with Graves' disease have at least one abnormal liver function test 1, 3
- ALT elevation specifically: 26-45.8% of patients 1, 2
- AST elevation: 17% of patients 2
- Alkaline phosphatase (ALP) elevation: Most common abnormality at 25-52.3% 1, 4, 2
- Gamma-glutamyl transpeptidase (GGT) elevation: 23.3-24% 4, 2
Types of Liver Dysfunction in Graves' Disease
The pattern of liver dysfunction in Graves' disease can be categorized as:
Risk Factors for Hepatic Dysfunction in Graves' Disease
Several factors increase the risk of developing liver function abnormalities in Graves' disease:
- Older age 1
- Longer duration of Graves' hyperthyroidism 1
- Higher free triiodothyronine (FT3) levels 1
- Higher thyrotrophin receptor antibody (TRAb) concentration 1, 3
Mechanism and Progression
The relationship between TRAb and liver dysfunction is significant:
- Higher TRAb levels correlate with increased AST, ALP, γ-GTP, and bilirubin levels 3
- Patients with high TRAb levels have greater odds of developing liver biochemical abnormalities (OR = 1.069,95% CI 1.019-1.113) 3
Clinical Course and Treatment Response
The pattern of liver function test abnormalities changes during treatment:
- After treatment with antithyroid drugs, GGT levels tend to normalize 4
- However, ALP levels may actually increase after treatment until the euthyroid state is achieved 4, 5
- AST and ALT may initially worsen after starting antithyroid drugs (observed in 53.3% of patients) but typically normalize even with continued treatment 5
- Patients with mild hepatic dysfunction or hepatocellular injury type are more likely to attain normal liver function after radioactive iodine (I-131) treatment 1
- Liver function normalization is more likely in patients whose hyperthyroidism is successfully treated 1
Clinical Implications
- Distinguishing between drug-induced liver injury and thyrotoxicosis-related liver dysfunction can be challenging
- Serial changes in liver function tests in both Graves' disease and painless thyroiditis suggest that increases in AST and ALT after starting antithyroid therapy may be related to changes in thyroid function rather than drug side effects 5
- Monitoring liver function is essential in patients with Graves' disease, especially those with risk factors for hepatic dysfunction
Understanding the prevalence and pattern of liver function abnormalities in Graves' disease is important for appropriate management and avoiding unnecessary discontinuation of antithyroid medications.