title: The validity of the Rheumatoid Arthritis Quality of Life (RAQoL) questionnaire.
abstract: OBJECTIVE
  To examine further the usefulness of a 30-item disease-specific quality of life (QoL) questionnaire in patients with rheumatoid arthritis (RA).
  
  
  METHODS
  The Rheumatoid Arthritis Quality of Life (RAQoL) questionnaire was applied to two groups consisting of 210 and 300 patients with RA, one group with increasing difficulty in performing activities of daily living and one group with stable disease. The associations between the RAQoL and measures of utility, QoL, functional status and disease activity were evaluated. Factor analysis was carried out to investigate if one or more QoL dimensions could be distinguished within this questionnaire.
  
  
  RESULTS
  Similar results regarding the association between the RAQoL and different sets of outcome measures were found in the two groups of patients. Regression analysis showed that about 75% of the variance of the RAQoL could be explained with variables of QoL, functional status and disease activity. Physical contact could be distinguished as a separate dimension within the RAQoL, in addition to the dimensions mobility/energy, self-care and mood/emotion.
  
  
  CONCLUSIONS
  The RAQoL is a valid instrument for measuring QoL in different populations of patients with RA. Physical contact, a dimension that is not covered by other common instruments in RA, could be distinguished as a separate dimension within the questionnaire.
authors.affiliation: Department of Rheumatology, Leiden University Medical Center, Leiden, The Netherlands.
authors.forename: G J
authors.initials: GJ
authors.lastname: Tijhuis
authors.forename: Z
authors.initials: Z
authors.lastname: de Jong
authors.forename: A H
authors.initials: AH
authors.lastname: Zwinderman
authors.forename: W M
authors.initials: WM
authors.lastname: Zuijderduin
authors.forename: L M
authors.initials: LM
authors.lastname: Jansen
authors.forename: J M
authors.initials: JM
authors.lastname: Hazes
authors.forename: T P
authors.initials: TP
authors.lastname: Vliet Vlieland
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001172:Arthritis, Rheumatoid / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D011788:Quality of Life; D015203:Reproducibility of Results; D011795:Surveys and Questionnaires / Q000592:standards*