The prevalence and related factors of fatigue in patients with COPD: a systematic review

BACKGROUND: Fatigue is a distressing symptom in patients with COPD. Little is known about the factors that contribute to fatigue in COPD. This review summarises existing knowledge on the prevalence of fatigue, factors related to fatigue and the instruments most commonly used to assess fatigue in COPD. METHODS: Pubmed, PsycINFO, EMBASE, Cochrane and CINAHL databases were searched for studies from inception up to 7 January 2020 using the medical subject headings “COPD” and “Fatigue”. Studies were reviewed in accordance with PRISMA guidelines. RESULTS: 196 studies were evaluated. The prevalence of fatigue ranged from 17–95%. Age (r=−0.23 to r=0.27), sex (r=0.11), marital status (r=−0.096), dyspnoea (r=0.13 to r=0.78), forced expiatory volume in 1 s % predicted (r=−0.55 to r=−0.076), number of exacerbations (r=0.27 to r=0.38), number of comorbidities (r=0.10), number of medications (r=0.35), anxiety (r=0.36 to r=0.61), depression (r=0.41 to r=0.66), muscle strength (r=−0.78 to r=−0.45), functional capacity (r=−0.77 to r=−0.14) and quality of life (r=0.48 to r=0.77) showed significant associations with fatigue. CONCLUSIONS: Fatigue is a prevalent symptom in patients with COPD. Multiple physical and psychological factors seem to be associated with fatigue. Future studies are needed to evaluate these underlying factors in integral analyses in samples of patients with COPD.