The Evaluation of Carotid Intima Thickness in Clinical and Subclinical Hypothyroidism and Effects of Thyroid Hormone Treatment

Abstract

Objectives: In this study, our aim was to investigate the CA-IMT in clinical hypothyroidism(CH) and subclinical hypothyroidism(SCH) and the effects of L-thyroxine replacement. Materials and methods: The study group consisted of 20 patients with clinical hypothyroidism(CH group) and 20 patients with subclinical hypothyroidism(SCH group) and 20 patients with with normal thyroid hormone function tests (control group). Serum TSH, fasting glucose, lipid profile(total cholesterol, HDL-cholesterol, LDL-cholesterol, and triglyceride),HbA1c,insulin,HOMA and carotid intima media thickness(CA-IMT) of all subjects were measured at admission. Thereafter, all hypothyroid patients received L- thyroxine treatment. The previous tests were re-examined after achievement of euthyroidism for 6 months. The results of the tests before and after L- thyroxine treatment were compared. Results: The levels of TSH, total cholesterol, triglyceride, LDL for CH and SCH group were statistically different before and after treatment(p≤ 0.05). The levels of glucose, HDL,VLDL, HbA1c, insulin and HOMA for CH and SCH group were similar before and after treatment(p≥ 0.05). The difference of CA-IMT for both sides before and after treatment was statistically significant(p ≤0.05). Conclusion: This study suggests that subjects with clinical and subclinical hypothyroidism are characterized by an increment in the CA-IMT resulting from an adverse lipid profile, which can be reversed by thyroid hormone replacement. So, thyroid hormone replacement may be helpful to prevent or at least slow down atherosclerosis in hypothyroid subjects.