title: The Effect of Fatigue and Fatigue Intensity on Exercise Tolerance in Moderate COPD.
abstract: Fatigue is one of the most disabling symptoms in COPD, but little is known about the impact of fatigue on functional disability. We explored the impact of fatigue and fatigue intensity on exercise tolerance after adjusting for other factors using multivariate analysis and compared it to that of dyspnoea.
  
  
  
  A total of 119 patients with mainly moderate-severe stable COPD (38 % women, mean age 66 years) were enrolled. We used the Medical Research Council dyspnoea scores (MRC), Manchester COPD fatigue scale (MCFS) and its three dimensions, Borg scales for fatigue and dyspnoea, six-minute walk distance (6MWD), St George's Respiratory Questionnaire, the BODE index, and the Centre for Epidemiological Study on Depression scale (CES-D), and we measured spirometry, blood gases, systemic inflammatory markers and fat-free mass index (FFMI).
  
  
  
  Fatigue measured using the MCFS was associated with 6MWD and explained 22 % of the variability in 6MWD (p < 0.001). Fatigue remained associated with 6MWD after adjusting for MRC dyspnoea, FFMI and FEV1, FVC, PaO2, PaCO2, CES-D, TNF-alpha, smoking status, age and gender. We found that 33, 50 and 23 % of patients reported an increase by 2 scores on Borg scales for fatigue, dyspnoea or both at the end of the 6MWT. Fatigue scores (both before and after the 6MWT) were negatively correlated with 6MWD after adjusting for FEV1, FFMI, CES-D score and age (p = 0.007 and 0.001, respectively).
  
  
  
  In moderate stable COPD, fatigue may be a central driver of functional disability, to the same extent as dyspnoea.
authors.affiliation: Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Academic Health Science Centre, The University of Manchester and University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK. Khaled.Al-shair@manchester.ac.uk.|Respiratory Research Group, 2nd floor The Education and Research Centre, South Manchester University Hospitals Trust, Manchester, M23 9LT, UK. Khaled.Al-shair@manchester.ac.uk.
authors.forename: Khaled
authors.initials: K
authors.lastname: Al-Shair
authors.affiliation: Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Academic Health Science Centre, The University of Manchester and University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK.
authors.forename: Umme
authors.initials: U
authors.lastname: Kolsum
authors.affiliation: Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Academic Health Science Centre, The University of Manchester and University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK.
authors.forename: Dave
authors.initials: D
authors.lastname: Singh
authors.affiliation: Centre for Respiratory Medicine and Allergy, Institute of Inflammation and Repair, Manchester Academic Health Science Centre, The University of Manchester and University Hospital of South Manchester, NHS Foundation Trust, Manchester, UK.
authors.forename: Jørgen
authors.initials: J
authors.lastname: Vestbo
mesh_terms: D000368:Aged; D002097:C-Reactive Protein / Q000378:metabolism; D004417:Dyspnea / Q000209:etiology / Q000503:physiopathology*; D017079:Exercise Tolerance; D005221:Fatigue / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D005541:Forced Expiratory Volume; D006801:Humans; D008297:Male; D008875:Middle Aged; D029424:Pulmonary Disease, Chronic Obstructive / Q000150:complications / Q000503:physiopathology*; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires; D014409:Tumor Necrosis Factor-alpha / Q000097:blood; D000070857:Walk Test
chemical_list: D014409:Tumor Necrosis Factor-alpha; D002097:C-Reactive Protein