Specific fatigue-related items in self-rating depression scales do not bias an association between depression and fatigue in patients with coronary artery disease.
Self-rating instruments for depression include questions targeting fatigue, which is a common symptom of coronary artery disease (CAD) patients. We evaluated if specific fatigue-related questions in self-reported instruments of depression bias an association between fatigue and depression in CAD patients. A total of 1470 CAD patients attending cardiac rehabilitation program were evaluated for fatigue using the Multidimensional Fatigue Inventory (MFI-20) and for symptoms of depression using the depression subscale of the Hospital Anxiety and Depression scale (HADS-D) and the Beck Depression Inventory-II (BDI-II). There was moderate correlation in MFI-20 scores vs. HADS-D scores and in MFI-20 scores vs. BDI-II scores, with stronger association in patients with less severe heart failure when compared to patients with more severe heart failure. Removal of questions targeting fatigue from the HADS-D and the BDI-II did not significantly change the association. Fatigue-related items should not be removed from the HADS-D and the BDI-II when evaluating CAD patients for depressive symptoms.