BACKGROUND: Increased rates of depression are reported in coronary artery 
disease (CAD). In heart disease, depression increases disability, reduces 
quality of life, and increases mortality.
HYPOTHESIS: The study was undertaken to examine the relationship between 
depression and thyroid axis function in patients with CAD.
METHODS: In all, 73 patients with CAD, consecutively admitted to a cardiac 
rehabilitation hospital, were assessed for depression using the Hospital Anxiety 
and Depression scale (HADS). Blood was drawn for assessment of thyroid axis 
hormones and the N-amino terminal fragment of the pro-B-type natriuretic peptide 
(NT-pro BNP).
RESULTS: The patients with CAD with depressive symptoms had a higher prevalence 
of cardiac failure (p = 0.04), higher NT-pro BNP concentrations (p = 0.02), and 
lower free triiodothyronine (T3) concentrations (p = 0.04) than patients with 
CAD but without depressive symptoms. They also showed a strong trend (p = 0.058) 
toward a higher incidence of the low T3 syndrome. Higher NT-pro BNP 
concentrations were related to lower total T3 concentrations (r = -0.294, p = 
0.011) and to higher reverse T3 concentrations (r = 0.353, p = 0.002). In men, 
higher scores of depression were related to lower total T3 concentration (r = 
-0.289, p = 0.034) and to higher NT-pro BNP concentration (r = 0.380, p = 
0.005).
CONCLUSION: These findings suggest that symptoms of depression in patients with 
CAD are associated with changes in thyroid axis function and with cardiac 
impairment, especially in men.