In people with coronary artery disease, the association between endocrine measures and fatigue is not well understood. We evaluated possible associations of fatigue and exercise capacity with function of adrenal axis and thyroid axis.
Sixty-five men and 18 women (mean age 55 years) attending a rehabilitation program were examined using the Multidimensional Fatigue Inventory, Dutch Exertion Fatigue Scale, and the Hospital Anxiety and Depression Scale. Exercise capacity was measured using a bicycle ergometer procedure. Serum concentrations of free triiodothyronine (T3), free thyroxine (T4), morning cortisol, afternoon cortisol, and change in cortisol concentrations (ΔCortisol) were measured.
In univariate regression analysis, lower free T4 concentrations were associated with general and exertion fatigue, lower free T3 concentrations were associated with general and physical fatigue, and lower ΔCortisol was associated with mental fatigue. After adjusting for age, sex, body mass index, hypertension, previous myocardial infarction, heart failure, diabetes, New York Heart Association functional class, depressive symptoms, and anxiety symptoms, lower free T3 concentrations remained associated with physical fatigue (β = −.224, p = .03); lower free T4 concentrations, with exertion fatigue (β = −.219, p = .03); and lower morning cortisol and lower ΔCortisol concentrations, with mental fatigue (β = −.193 [p = .03] and β = −.180 [p =.04], respectively). Exercise capacity was not associated with endocrine factors.
In coronary artery disease patients, increased thyroid hormone concentrations are associated with decreased physical fatigue and decreased exertion fatigue, and increased cortisol concentrations with decreased mental fatigue. Exercise capacity is not associated with endocrine factors.
CAD = coronary artery disease
T3 = triiodothyronine
T4 = thyroxine
CFS = chronic fatigue syndrome
ΔCortisol = change in cortisol concentration
HPA = hypothalamic-pituitary-adrenal
TSH = thyroid-stimulating hormone
NYHA = New York Heart Association
MI = myocardial infarction
BMI = body mass index
HADS = Hospital Anxiety and Depression Scale
MFI-20 = Multidimensional Fatigue Inventory
DEFS = Dutch Exertion Fatigue Scale
From the Behavioral Medicine Institute, Lithuanian University of Health Sciences, Palanga, Lithuania (A.B., V.G., A.P., J.B., R.B.); Departments of Psychiatry, University of North Carolina at Chapel Hill, Chapel Hill, California (A.B., A.J.P.); and Clinic of Cardiology, Lithuanian University of Health Sciences, Kaunas, Lithuania (R.Z.).
Address correspondence and reprint requests to Adomas Bunevicius, MD, Department of Psychiatry, University of North Carolina at Chapel Hill, CB 7175, Medical School Wing D, Chapel Hill, NC 27599-7175. E-mail: firstname.lastname@example.org
This work, in part, is being supported by the PONTE project and has been funded by the European Commission’s Seventh Framework Programme under contract number 247945. This manuscript expresses the opinions of the authors and not necessarily those of the European Commission. The European Commission is not liable for any use that may be made of the information contained in this manuscript.
Conflicts of interest: None.
Received for publication August 8, 2012; revision received June 13, 2012.