Patient perspective: reasons and methods for measuring fatigue in rheumatoid arthritis.

The experience of fatigue has been reported by a large proportion of people with rheumatoid arthritis (RA), and it is often the most important problem for individual patients. A systematic analysis of patient focus group discussions revealed 3 overarching themes: fatigue is overwhelming and different from normal tiredness; it permeates every sphere of life; and self-management is variable, but professional support is rare. A systematic search for articles measuring fatigue discovered 23 scales, 6 of which have sufficient evidence of validity to pass the OMERACT filter. Some preliminary data indicate that fatigue measurement is sensitive to change induced by some interventions in RA. This issue, and the question of whether measuring fatigue adds additional information to measurements made using the current core set of measures, will be addressed at OMERACT 8.