Relation of subclinical hypothyroidism with Coronary Artery Calcium Score

Subclinical hypothyroidism (SCH) is a minor form of hypothyroidism disorder that has no obvious clinical symptoms. SCH is linked to premature atherosclerosis and a higher prevalence of coronary artery disease - a leading killer. Our aim is to investigate the relation of SCH and coronary artery disease (CAD) by measuring the coronary artery calcium score (CACS) detected by multi-slice CT coronary angiography in apparently healthy subjects Patients and Methods: A total of asymptomatic 100 (50 SCH and 50 euthyroid (EU)), without known coronary artery disease and meet our inclusion criteria from December 2018 to November 2019 at Mustafa Kamel Military Hospital outpatient clinic were enrolled in this study. Detailed history, laboratory investigations as: thyroid, lipid profile, renal function test, and HA1C were recorded. Framingham Risk Score (FRS) was calculated, CACS analysis by cardiac CT scan was performed on all subjects. SCH and EU groups were comparable when it came to age, gender, BMI, prevalence of diabetes, systemic hypertension, hypercholesterolemia, and smoking. There were no differences between the two groups in terms of mean Ca score, type of affected coronary arteries, or the number of affected coronary arteries, and the frequency of Ca score > 100 was not higher in the SCH group. The mean Ca score and the probability of a Ca score > 100 were higher in the SCH group when just the intermediate and high FRS were evaluated (P = 0.00). Serum TSH was positively correlated with CACS in intermediate/high FRS group (rs=0.86, P=0.001*). In conclusion, our findings highlight the importance of SCH and TSH level as predictive risk factors for coronary artery disease particularly in the intermediate/high FRS subgroups.