OBJECTIVETo survey the association of serum free triiodothyronine (FT3) level with coronary artery calcification and major adverse cardiac events (MACE) in outpatients with suspected coronary artery disease (CAD).

METHODSA total of 577 outpatients with suspected CAD, who underwent dual-source computed tomography and FT3 detection were included, patients were followed up for 8-29 months for the major adverse cardiac events (death, MI, PCI, CABG). These patients were divided into low FT3 ( < 3.5 pmol/L, n = 126) and normal FT3 ( ≥ 3.5 pmol/L, n = 451) group based on the FT3 level, and divided into CACS > 100 (n = 235) and CACS ≤ 100 (n = 342) group based on the coronary artery calcium score (CACS). Related factors to CACS and MACE were analyzed using logistic regression (stepwise) analysis.

RESULTSCACS (146.7 (55.8, 599.1) vs. 34.8 (0, 261.9), P < 0.001) and MACE (7.9% (10/126) vs. 2.0% (9/451) , P = 0.003) were significantly higher in the low FT3 group than in normal FT3 group. Logistic regression analysis demonstrated that the FT3 levels are inversely associated with the CACS (OR = 0.442, 95%CI = 0.317-0.618, P < 0.001). Kaplan-Meier analysis displayed that patients with low FT3 levels had a lower cumulative survival rate than patients with normal FT3 levels (P = 0.005), and patients with CACS > 100 also had a lower cumulative survival rate than patients with CACS ≤ 100(P < 0.001).

CONCLUSIONSFT3 levels are associated with coronary artery calcification scores and the incidence rate of MACE in patients with suspected coronary artery disease. A low FT3 level is considered as an important risk factor of high calcification scores and MACE.