Fatigue assessments in rheumatoid arthritis: comparative performance of visual analog scales and longer fatigue questionnaires in 7760 patients.
OBJECTIVE
Fatigue has been recognized as an important domain in rheumatoid arthritis (RA) clinical trials and in patient care and outcome. However, lengthy fatigue questionnaires cannot be easily used in clinical care, and there are no data for the comparative performance of various short and long questionnaires. We compared a single-item visual analog scale (VAS) with 3 longer fatigue questionnaires, investigating 4 fatigues scales: the Multi-dimensional Assessment of Fatigue (MAF), the vitality scale from the Medical Outcomes Study Short Form 36 (SF-36), the Brief Fatigue Inventory (BFI), and the VAS.


METHODS
Participants in a longitudinal outcome study of RA (N = 7760) completed the 4 questionnaires, and a subset of 5155 completed the same fatigue scales 6 months later.


RESULTS
All questionnaires were highly correlated and were correlated at similar levels with clinical variables. The 3 longer questionnaires had slightly greater reliability in cross-sectional analyses, but the VAS was as good as or better than the longer questionnaires when sensitivity to change was considered.


CONCLUSIONS
The single item VAS performs as well as or better than longer scales in respect to sensitivity to change, and is at least as well correlated with clinical variables as longer scales. The VAS fatigue scale is suitable for routine use in clinical care, an advantage that is lacking for the other scales. These results do not indicate advantages for longer fatigue scales compared with the VAS.
National Data Bank for Rheumatic Diseases, University of Kansas School of Medicine, Wichita, Kansas, USA. fwolfe@arthritis-research.org
Frederick
F
Wolfe
D000203:Activities of Daily Living; D000368:Aged; D001172:Arthritis, Rheumatoid / Q000503:physiopathology*; D005221:Fatigue; D006801:Humans; D008875:Middle Aged; D010147:Pain Measurement; D015203:Reproducibility of Results; D012720:Severity of Illness Index; D013223:Statistics as Topic; D011795:Surveys and Questionnaires