Simvastatın improves endothelial function in patents with subclinical hypothyroidism

Abstract

Patients with subclinical hypothyroidism (SCH) have impaired endothelial function probably related to dyslipidemia. The present study compares the effects of simvastatin versus levothyroxine (LT-4) treatment on lipid profile and endothelial function in patients with SCH. Fifty-nine patients with newly diagnosed SCH were enrolled. Patients were randomized into 3 groups to receive no treatment (n = 19), LT-4 (n = 20), or simvastatin (n = 20). We measured endothelium-dependent vasodilation (EDV) and endothelium-independent vasodilation (EIV) at baseline and after 8 months. Serum total cholesterol, triglycerides and LDL-cholesterol were significantly lower following simvastatin. EDV increased significantly in simvastatin treatment group (7.5% +/- 3.3% vs 14.0% +/- 4.5% (P < 0.01). The improvement of EDV correlated with the percent decrease of LDL-cholesterol (rho = 0.68, P < 0.01). Although LT-4 therapy caused a trend towards an increase in EDV compared to baseline, statistical significance was not achieved. EIV remained unchanged in all three groups. Simvastatin but not LT-4 treatment significantly improves EDV of the brachial artery and dyslipidemia in patients with SCH. Improvement in brachial artery endothelial function may be related in part to a hypolipidemic effect of simvastatin treatment.

Serum levels of nitrite/nitrate, lipid profile, and Fasting Plasma Glucose and their associations in subclinical hypothyroid women before and after a two month treatment by levothyroxine

“…Our results did not reveal any significant differences of LDL levels in patients in comparison to control group. Several studies revealed contemporary elevation of TC and LDL [36][37][38], although many studies could not detect any alterations of lipid profile in sHT patients in comparison to control group [39][40][41], exactly similar to our investtigation that we could not demonstrate any differences in lipid profile of sHT and control group. In spite of all that, our study detected significant differences in serum TG levels between before and after treatment groups so that TG levels decreased meaningfully after treatment.…”

Evaluation of the effect of l-thyroxin therapy on endothelial functions in patients with subclinical hypothyroidism

“…This study was important in demonstrating the cellular and molecular effects of LT4 therapy on the atherosclerotic process. In contrast to these studies, Duman et al [18] observed no improvement in FMD after LT4 treatment in patients with SH. In some studies, TSH levels have been found to be inversely correlated with FMD value in SH patients [19,20].…”

Statin intolerance – an attempt at a unified definition. Position paper from an International Lipid Expert Panel

“…Some data suggest that levothyroxine replacement therapy may exert a beneficial effect on total cholesterol (TC), LDL-C and other predictors of vascular risk in SCH [100]. Furthermore, it appears that in SCH, statins with or without levothyroxine, can improve endothelial function and reduce carotid intima media thickness, reliable markers associated with CVD risk [101]. However, statins may be related to muscle symptoms even in patients with SCH [102].…”