Introduction: Fatigue is a prominent symptom in COPD and it has distinctive features; however, there is a need for a robust scale to measure fatigue in COPD.
Methods: At baseline, 122 COPD patients (FEV1 52%, women 38%, mean age 66) completed a pilot fatigue scale covering a pool of 57 items and underwent a range of test, including indicators of mood and a short general fatigue questionnaire. All patients responded to the 57 items scale and it was readministered to a subset of 30 patients. The pilot scale was first subjected to constructive validated shortening steps and then to a principal components analysis.
Results: The Manchester COPD fatigue scale (MCFS) consists of 27 items, loading into three dimensions: physical, cognitive and psychosocial fatigue. We tested internal consistency (Cronbach's = 0.97) and test-retest repeatability (r = 0.94, p<0.001). It had significant convergent validity, correlating with the FACIT fatigue scale and fatigue in Borg scale at baseline and after 6 minute walk test (6MWT) (r= -0.81, 0.53 and 0.63, respectively, p=<0.001). Its scores were associated with BODE, SGRQ and MRC dyspnoea scores (r= 0.46, 0.8 and 0.51, respectively, p=<0.001). The scale demonstrated meaningful discriminating ability; patients who walked <350m in 6MWT as well as depressed patients ( 16 scores in CES-D) had nearly twice as high fatigue scores as those who walked 350m or were not depressed (p<0.001).
Conclusion: The Manchester COPD fatigue scale provides a simple, reliable and valid measurement of total and dimensional fatigue in moderate stable COPD.