Thyroid hormone and coronary artery disease: from clinical correlations to prognostic implications

Background: Overt thyroid dysfunction, hypothyroidism in particular, may lead to coronary artery disease (CAD). Whether more subtle anomalies of thyroid hormone metabolism influence the progression of CAD remains a matter of speculation. Hypothesis: The occurrence of CAD and long-term prognosis in patients without a history of either primary thyroid disease, myocardial infarction, or chronic heart failure is related to serum levels of biologically active free triiodothyronine (fT3). Methods: The cohort consisted of 1047 clinically and biochemically euthyroid patients (median age 65.6 y and 69% male) who underwent coronary angiography in our institute for suspected CAD. Results: Lower fT3 levels were predictive of both single-vessel (p = 0.012) and multivessel (p = 0.009) CAD. Through a multivariate logistic regression analysis, fT3 was still linked to the presence of CAD (hazard ratio [HR]: 0.48, 95% confidence interval [CI]: 0.34-0.68, p 0.001). After a mean follow-up of 31 months, the survival rate was95%and total mortality (log-rank 6.75, p