Gender-Dependent Association Between Thyroid Hormones and Severity of Coronary Artery Disease by SYNTAX Score

Thyroid function has been shown to be associated with cardiovascular diseases. Moreover, sex can influence on the association between thyroid function and other diseases. We aimed to evaluate the relationship between thyroid hormones and the severity of coronary artery disease (CAD) and outcomes. In a prospective study, patients with chest pain undergoing diagnostic coronary angiography were evaluated. Patients were categorized based on the number of involved coronary arteries. Moreover, the severity of CAD was quantitatively calculated using the Syntax score (SS). All patients were also followed up for 3-month duration. The level of TSH in 150 patients was significantly higher in females than males (3.1 [1.7, 5] versus 1.8 [1, 3.3] mU/L; P=0.002). There was significant correlation between THS and the SS among females (ρ=0.477, P<0.001), but not males. Among both sexes, thyroid hormones were comparable between those with or without events during follow-up. The main predictors of high SS values included age (odds ratio [OR] 1.060, 95% confidence interval [CI] 1.018-1.104; P=0.005) and female (OR 2.941, 95% CI 1.198-7.218). The main predictors of multivessel disease were age (OR 1.077, 95% CI 1.026-1.132), female (OR 5.853, 95% CI 1.880-18.222), thyroxin (OR 0.733, 95% CI 0.547-0.981), and thyrotropin (OR 1.333, 95% CI 1.079-1.647). Thyroid hormones are associated with the presence and the severity of CAD, but it might be sex-related. However, thyroid hormone levels could not predict short-term outcomes of patients.