Validation of the Functional Assessment of Chronic Illness Therapy Fatigue Scale relative to other instrumentation in patients with rheumatoid arthritis.
OBJECTIVE
This study validated a brief measure of fatigue in rheumatoid arthritis (RA), the Functional Assessment of Chronic Illness Therapy (FACIT) Fatigue Scale.


METHODS
The FACIT Fatigue was tested along with measures previously validated in RA: the Multidimensional Assessment of Fatigue (MAF) and Medical Outcomes Study Short-Form 36 (SF-36) Vitality. The sample included 636 patients with RA enrolled in a 24 week double blind, randomized clinical trial (RCT) of adalimumab versus placebo.


RESULTS
The FACIT Fatigue showed good internal consistency (alpha = 0.86 to 0.87), strong association with SF-36 Vitality (r = 0.73 to 0.84) and MAF (r = -0.84 to -0.88), and the ability to differentiate patients according to clinical change using the American College of Rheumatology (ACR) response criteria (ACR 20/50/70). Psychometric performance of the FACIT Fatigue scale was comparable to that of the other 2 fatigue measures. A minimally important difference in FACIT Fatigue change score of 3-4 points was confirmed in a separate sample of 271 patients with RA enrolled in a second double blind RCT of adalimumab versus placebo.


CONCLUSIONS
The FACIT Fatigue is a brief, valid measure for monitoring this important symptom and its effects on patients with RA.
Cella
David
D
Center on Outcomes, Research and Education, Evanston Northwestern Healthcare and Northwestern University, Evanston, Illinois 60201, USA. d-cella@northwestern.edu
Yount
Susan
S
Sorensen
Mark
M
Chartash
Elliot
E
Sengupta
Nishan
N
Grober
James
J
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000150:complications / Q000503:physiopathology*; D002908:Chronic Disease; D005221:Fatigue / Q000209:etiology / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011594:Psychometrics / Q000592:standards*; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D011795:Surveys and Questionnaires / Q000592:standards*