The Effect of Thyroxine Therapy on Cardiovascular Risk Factors in Patients with Subclinical Hypothyroidism

Abstract

Aim: Subclinical hypothyroidism (SH) has a deleterious effect on cardiovascular risk factors (CVR); however it should be treated or not is stil controversial. The aim of our study is to determine CVR in patients with SH, and to investigate the short term effect of thyroxine treatment on CVR. Material and Methods: Patients with SH (n=30), and age- and sex-matched control group (n=40) were included in this retrospective study. SH patients were treated by 50μg/day thyroxine for 3 months. Pre-treatment CVR was compared with post-treatment CVR. Results: Sex distribution and mean age were similar between control (female 66.7%; age 45.76±14.55 years) and SH (female 77.3%; age 45.23±12.02 years) groups (p>0.05). Body mass index (BMI) was high in SH group (32.66±5.57 kg/m2) than in control group (25.13±3.20 kg/m2, p<0.05). At baseline, serum glucose (83.76±9.51 vs 91.73±9.96 mg/dl), total cholesterol (162.36±13.41 vs 184.21±51.91 mg/dl), low-density lipoprotein-cholesterol (LDL-C; 91.73±22.04 vs 104.61±11.36 mg/dl), and C-reactive protein (hs-CRP; 1.53±0.66 vs 2.63±0.93 mg/L) levels were higher in SH group than in the control group (p<0.05). After treatment, BMI value decreased (31.35±5.54 kg/m2) along with decreasing serum LDL-C (97.30±9.63 mg/dl) and hs-CRP (1.96±0.42 mg/L) levels in SH group (p<0.05). Thyroid stimulating hormone was independently associated with LDL-C (OR=2.17,%95CI [1.26-2.54], p=0.005). Conclusion: In this study, it was determined that cardiometabolic disorders in patients with subclinical hypothyroidism partiel improved with thyroxine treatment. Thyroxine treatment may contribute to the reduction of increased cardiovascular risk in subclinical hypothyroidism.