Psychometric characteristics of the ankylosing spondylitis quality of life questionnaire, short form 36 health survey, and functional assessment of chronic illness therapy-fatigue subscale.

The authors have withdrawn this article from the public domain because the conclusions drawn may not be supported by the data. In the light of this situation, BioMed Central regrets that this article is no longer available. The authors apologise to all parties for the inconvenience.