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.
Conclusion: 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.