Abstract
Objective
To assess responsiveness of the Psoriatic Arthritis Quality of Life tool (PsAQoL) and add further data regarding the construct validity of PsAQoL.
Methods
Twenty-eight patients with PsA underwent clinical assessment over a period of 6 months after change of disease modifying therapy, usually to methotrexate. Measures of outcome included PsAQoL, Health Assessment Questionnaire (HAQ), and assessment of disease activity.
Results
PsAQoL revealed significant change at 3 and 6 months. Standardized response mean was large at 3 months and small at 6 months. There was strong correlation with other patient-derived measures such as the HAQ and Patient Global at all timepoints. Disease Activity Score-28 and Physician Global showed a relationship with PsAQoL at 3 and 6 months, while a tender joint count relationship was seen only at 6 months.
Conclusion
The PsAQoL now has responsiveness data and a measure of construct validity to sit alongside previously demonstrated reliability data. Our study has compared the change characteristcs within a group of patients. The next step in the development will require a placebo controlled trial to test discrimination between patients undergoing active treatment or taking placebo.
Key Indexing Terms:Footnotes
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Dr. Healy was supported by a scholarship from the Rose Hellaby Trust, New Zealand. Financial support for the study was provided by the Group for Research and Assessment of Psoriasis and Psoriatic Arthritis (GRAPPA) and Sanofi-Aventis.
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P.J. Healy, MBChB, FRACP, Rose Hellaby Research Fellow; P.S. Helliwell, DM, PhD, FRCP, Senior Lecturer in Rheumatology.
- Accepted for publication February 27, 2008.