Assessment of Clinical and Biochemical Cardiac Risk Factors in Patients with Subclinical Hypothyroidism: A Cross-sectional Study

Abstract

Introduction: Cardiovascular diseases (CVD) are among the leading causes of morbidity and mortality in the current era, and the focus is gradually shifting towards identifying the risk factors and pathways leading to CVD. While hypothyroidism has been extensively studied and linked to CVD risk, the association between subclinical hypothyroidism and CVD risk factors is not well established. Aim: To investigate the association between subclinical hypothyroidism and cardiac risk factors such as obesity indicators {Body Mass Index (BMI) and Waist-hip Ratio (WHR)}, blood pressure, and lipid parameters. Materials and Methods: This cross-sectional study was conducted at the Department of Medicine, ESI PGIMSR, Basaidarapur, New Delhi, India, from December 2020 to April 2022. The study included 200 patients, with 100 patients recruited in the subclinical hypothyroidism group (Thyroid Stimulating Hormone (TSH) >4.8 μIU/mL with normal fT4) and 100 patients with euthyroid status (TSH 0.5-4.8 μIU/mL and normal fT4) included in the comparison group. Both groups were assessed for CVD risk factors including obesity indicators (BMI and WHR), blood pressure, and lipid parameters. The two groups were analysed for statistical significance using Student’s t-test. Results: Both groups had similar age distributions. However, there was a greater percentage of female patients in the subclinical hypothyroidism group (61%) compared to the euthyroid group (52%). As expected, TSH levels in the subclinical hypothyroidism group were significantly higher than in the euthyroid group. The subclinical hypothyroidism group recorded significantly higher mean values of BMI, Systolic Blood Pressure (SBP), Diastolic Blood Pressure (DBP), total cholesterol, and triglycerides, which were higher by 18%, 17%, 17%, 41%, and 16% compared to the euthyroid group, respectively. Other parameters like WHR and Low-Density Lipoprotein-Cholesterol (LDL-C) were found to be raised in subclinical hypothyroidism compared to the euthyroid group, while High-Density Lipoprotein-Cholesterol (HDL-C) levels were significantly lower by 16% in subclinical hypothyroidism. Conclusion: Subclinical hypothyroidism is significantly associated with cardiac risk factors like obesity indicators (BMI and WHR), blood pressure, and lipid parameters.