Abstract
BACKGROUND: Fatigue is one of the most common symptoms among subjects with chronic obstructive pulmonary disease (COPD), but is rarely identified in clinical practice. The aim of this study was to evaluate the association between fatigue and health-related quality of life (HRQoL) assessed with clinically useful instruments, both among subjects with and without COPD. Further, to investigate the association between fatigue and the COPD Assessment Test (CAT)-energy question. METHODS: Data were collected in 2014 within the population-based OLIN COPD study. Subjects with ( n = 367) and without ( n = 428) COPD participated in clinical examinations including spirometry and completed questionnaires about fatigue (FACIT-Fatigue, clinically relevant fatigue ⩽43), and HRQoL (EQ-5D-VAS, lower score = worse health; CAT, lower score = fewer symptoms/better health). RESULTS: Subjects with clinically relevant fatigue had worse HRQoL measured with EQ-5D-VAS, regardless of having COPD or not. Decreasing EQ-5D-VAS scores, any respiratory symptoms and anxiety/depression were associated with clinically relevant fatigue also when adjusted for confounders. Among subjects with COPD, clinically relevant fatigue was associated with increasing total CAT score, and CAT score ⩾10. The proportion of subjects with clinically relevant fatigue increased significantly, with a higher score on the CAT-energy question, and nearly 50% of those with a score of 2, and 70% of those with a score of ⩾3, had clinically relevant fatigue. CONCLUSIONS: Fatigue was associated with respiratory symptoms, anxiety/depression and worse HRQoL when using the clinically useful instruments EQ-5D-VAS and CAT. The CAT-energy question can be used to screen for fatigue in clinical practice, using a cut-off of ⩾2.