Lipid profile and early predictors of endothelian dysfunction in hypothyroidism against the TSH level within reference range

Abstract

Hypothyroidism is associated with premature atherosclerosis and cardiovascular disease. High levels of total cholesterol, low-density lipoprotein cholesterol (LDL-C), triglycerides and recently, homocysteine (Hcy) and C-reactive protein (CRP) emerged as additional cardiovascular risk factors. Sixty ambulatory patients with primary hypothyroidism receiving levothyroxine (L-T4) participated in the study. Patients were divided into 2 groups according to their TSH level. The first group was in TSH low-normal range (0.4–2.0 mU/l), the second in upper-normal (2.1–4.0 mU/l) range. We analyzed the results of lipid profile data, CRP and HCY levels at baseline and in 3 months. With a small-dose changes we cross the groups to compare the results. Patients in upper-normal range group had significantly higher levels of total cholesterol (p = 0.002), LDL-C (p = 0.02), triglycerides (p = 0.03) at baseline. After decreasing the dose of L-T4 in group with low-normal TSH range there were no significant difference in levels of total cholesterol and triglycerides. After dose-changing the level of LDL-C was significantly higher in group with upper-normal TSH range (p = 0.02). After increasing the L-T4 dose in group with upper-normal TSH range we didn't find any significant differences in lipid profile level, but the early predictors of endothelium dysfunction were sig-nificantly lower in group with low-normal TSH range: CRP (p = 0.004), HCY (p =0.05). Conclusion: Small-changes in L-T4 dose which help to achieve the low-normal TSH range leads to significantdecrease in levels of early predictors of en-dothelium dysfunction – C-reactive protein and homocysteine.