Endocrine Abstracts

Introduction: Subjective fatigue is a common symptom in patients with coronary artery disease (CAD) and has a significant negative effect on quality of life of CAD patients. However, currently there are no studies evaluating possible association between endocrine measures and subjective fatigue in CAD patients. Therefore the aim of the current study was to evaluate possible associations of subjective fatigue with function of adrenal axis and thyroid axis in CAD patients.

Methods: Eighty-three CAD patients (65 men, 18 women; aged 55±9 years) attending a rehabilitation program within two weeks after inpatient treatment for acute coronary syndromes were evaluated for demographic and clinical characteristics, for subjective fatigue using the Multidimensional Fatigue Inventory and Dutch Exertion Fatigue Scale, for depressive and anxiety symptoms using the Hospital Anxiety and Depression Scale, and for serum concentrations of free tri-iodothyronine (T3), free thyroxine (T4), morning cortisol, afternoon cortisol and change in cortisol concentrations (delta-Cortisol).

Results: In univariate regression analysis lower free T4 concentrations were associated with greater general fatigue and exertion fatigue; lower free T3 concentrations were associated with greater general fatigue and physical fatigue; and lower delta-Cortisol was associated with greater mental fatigue.

After adjusting for age, gender, body mass index, hypertension, previous myocardial infarction, heart failure, New York Heart Association functional class, depressive and anxiety symptoms, lower free T3 concentrations remained associated with greater physical fatigue (β=−0.224, P=0.03); lower free T4 concentrations - with greater exertion fatigue (β=−0.219, P=0.03); and lower morning cortisol concentrations - with greater mental fatigue (β=−0.193, P=0.03).

Conclusions: In CAD patients function of adrenal axis and thyroid axis are associated with subjective fatigue independently from cardiac functional class or symptoms of depression and anxiety. Specifically, decreased thyroid hormone concentrations are associated with greater physical fatigue and greater exertion fatigue; and decreased cortisol concentrations are associated with greater mental fatigue.

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.