BENEFICIAL EFFECTS OF LEVOTHYROXINE IN THE TREATMENT OF SUBCLINICAL HYPOTHYROIDISM
Introduction:Increased cardiovascular risk in thyroid dysfunction is associated with disorders of lipid and lipoproteins, endothelial dysfunction, metabolic, hormonal, hemodynamic changes and coagulation disorders.
Subclinical hypothyroidism is characterized by a suprarnormal level of TSH with normal levels of thyroid hormones. The correlation between subclinical hypothyroidism of the lipid profile and cardiovascular outcomes remains unclear. Several intervention studies assessed the effect of levothyroxine therapy on the lipid profile of patients with subclinical hypothyroidism and obtained conflicting results.
The aim of the research is to determine whether subclinical hypothyroidism is associated with the atherogenic lipid profile and whether these changes are reversible after the introduction of the L-thyroxine replacement therapy.
Method: The study included 51 patients over 50 years of age with subclinical hypothyroidism. All the participants were subjected to an examination programme which included a detailed anamnesis and physical examination, laboratory tests (total cholesterol, LDL cholesterol, HDL cholesterol, triglycerides, T3, T4, TSH). After eight weeks of levothyroxine therapy, the same laboratory parameters were determined in the patients.
Results: Subjects with subclinical hypothyroidism had high average values: TSH (12.77 + 2.78 mIU / ml), total cholesterol (7.55 0.79 mmol / l), LDL cholesterol (5.03 0.61 mmol / l), triglycerides (2.48 1.01 mmol / l); and the average value of HDL cholesterol was within reference values (1.12 0.21 mmol / l). After eight weeks of levothyroxine replacement therapy, there was a statistically significant reduction of average values (p <0.0001): TSH (3.83 1.33 mIU / ml), total cholesterol (6.28 0.96 mmol / l), LDL cholesterol ( 4.03 0.70 mmol / mmol / l l), triglycerides (1.98 0.87 mmol / l); and the average value of HDL cholesterol increased significantly (p <0.0001) (1.32 0.22 mmol / l).
Conclusion: Subjects with subclinical hypothyroidism have the atherogenic lipid profile which is corrected after the levothyroxine treatment. Subclinical hypothyroidism can be considered a disorder that leads to increased cardiovascular risk.
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