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The online version of this article (doi:10.1186/1477-7525-10-100) contains supplementary material, which is available to authorized users.
Khaled Al-shair has no conflict of interest to declare in relation to this work. Hana Muellerova is an employee of GlaxoSmithKline R&D; she owns shares and stock option of GlaxoSmithKline. Janelle Yorke has no conflict of interest to declare in relation to this work. Stephen Rennard has served as a consultant or participated in advisory boards for: ABIM, Able Associates, Adelphi Research, Almirall, APT, Aradigm, Argenta, AstraZeneca, BI (ACCP), Biostrategies, BoomCom, Britnall and Nicolini, Capital Research, Chiesi, Clinical Advisors, CommonHealth, Complete Medical Group, Consult Complete, COPDForum, DataMonitor, Decision Resources, Defined Health, Dey, Dunn Group, Easton Associates, Enterprise Analysis, Equinox, Forest, Fulcrum, Gerson Lehman, GSK, Guidepoint, Hoffman LaRoche, IMS, Informed, Inspire, Insyght, KOL Connection, Leerink Swan, M. Pankove, MDRx Financial, MedaCorp, Medimmune, Mpex, Novartis, Nycomed, Oriel, Otsuka, Pearl, Pennside Partners, Pfizer, Pharma Ventures, Pharmaxis, Pick Research, Prescott, PwC, Propagate, Pulmatrix, Pulmonary Reviews, Quadrant, Reckner Associates, Recruiting Resource, Reviews and Trends in COPD/Convergent Health Solutions, Roche, Sacoor, Schering, Schlesinger Medical, Scimed, Smith Research, Sudler and Hennessey, Talecris, Theravance, UBC, Uptake Medical, Vantage Point. He has received lecture fees from: AAAAI, Am Col Osteopathic Physicians, Asan Medical Center, ATS, AstraZeneca, California Soc Allergy, Convergent Health Solutions for Reviews and Trends in COPD, COPD Foundation, Creative Educational Concepts, Dey, Duke, France Foundation, Information TV, University of California-Los Angeles, Network for Continuing Education, Novartis, Nycomed, Otsuka, Pfizer, Sarasota Mem Hospital, Spanish Thoracic Society, University of Washington, University of Alabama-Birmingham, University of Pittsburgh, University of British Columbia, University of California-Davis, VA Sioux Falls. He has received industry-sponsored grants from: AstraZeneca, Biomarck, Centocor, GlaxoSmithKline, Mpex, Nabi, Novartis, Otsuka, Pfizer. Nicola A. Hanania has received research grant support as well as served as a consultant and on the speaker bureau for GSK. Emiel Wouters has recevied honoraria for presenting and consulting from AstraZeneca, Boehringer-Ingelheim, GlaxoSmithKline, Novartis, Nycomed and Pfizer and his department has received research grants from GlaxoSmithKline. Amir Sharafkhaneh is on advisory board of GSK and Dey. Jørgen Vestbo has recevied honoraria for presenting and consulting from AstraZeneca, Boehringer-Ingelheim, Bioxydyn, Chiesi, GlaxoSmithKline, Novartis, Nycomed and Pfizer and his department has received research grants from GlaxoSmithKline; his wife has previously worked for several pharmaceutical companies, including GlaxoSmithKline.
KA participated in the study design and data collection, and performed the statistical analyses and wrote the manuscript. HM, JY, SR, EW, NH, AS and JV participated in study design, data analysis and the manuscript writing, editing and reviewing. All authors read and approved the manuscript.
Fatigue is a disruptive symptom that inhibits normal functional performance of COPD patients in daily activities. The availability of a short, simple, reliable and valid scale would improve assessment of the characteristics and influence of fatigue in COPD.
At baseline, 2107 COPD patients from the ECLIPSE cohort completed the Functional Assessment of Chronic Illness Therapy Fatigue (FACIT-F) scale. We used well-structured classic method, the principal components analysis (PCA) and Rasch analysis for structurally examining the 13-item FACIT-F.
Four items were less able to capture fatigue characteristics in COPD and were deleted. PCA was applied to the remaining 9 items of the modified FACIT-F and resulted in three interpretable dimensions: i) general (5 items); ii) functional ability (2 items); and iii) psychosocial fatigue (2 items). The modified FACIT-F had high internal consistency (Cronbach's α = 0.91) and it did not fit a uni-dimensional Rasch model, confirming the prior output from the PCA. The correlations between total score and each dimension were ≥ 0.64 and within dimensions ≥0.43 (p < 0.001 for all).
The original and modified FACIT-F had significant convergent validity; its scores were associated with SGRQ total score (0.69 and 0.7) and mMRC dyspnoea scores (0.48 and 0.47), (p = <0.001 for all). The scale had meaningful discriminating ability in identifying patients with poor exercise performance and more depressive symptoms.
The original and modified FACIT-F are valid and reliable scales in COPD. The modified version is shorter and measures not only total fatigue but also its sub-components in COPD.