• Louise Linde, Jan Sørensen, Mikkel Ostergaard, Kim Hørslev-Petersen, and Merete Lund Hetland.
• Department of Rheumatology, Copenhagen University Hospital, Hvidovre, Denmark. louiselinde@dadlnet.dk
• J Rheumatol. 2008 Aug 1;35(8):1528-37.

ObjectiveTo compare validity, reliability, and responsiveness of generic and disease specific health-related quality of life (HRQOL) instruments in rheumatoid arthritis (RA).MethodsTwo samples of patients completed the Medical Outcomes Study Short Form-36 Health Survey (SF-36), EuroQol (EQ)-5D, 15D, Rheumatoid Arthritis Quality of Life Scale (RAQoL), Health Assessment Questionnaire (HAQ), and visual analog scales (VAS) for pain, fatigue, and global RA. VALIDITY (convergent, discriminant, and known-groups) was evaluated in a cross-section of 200 patients. Reliability was evaluated by agreement (intraclass correlation coefficient; baseline to 2 weeks) and internal consistency (Cronbach's alpha); and responsiveness by the standardized response mean stratified on improvement, status quo, or deterioration in health status after 6 months in 150 patients followed longitudinally. Followup questionnaires (at 2 weeks and 6 months) included questions about changes in health status since baseline.ResultsThe cross-sectional sample included 77% women, median age 57 years (range 19-87), disease duration 6 years (0-58), with Disease Activity Score 28-joint count (DAS28) of 3.10 (1.21-6.47). The longitudinal sample included 80% women, median age 60 years (22-82).Validityall instruments discriminated between low, moderate, and high DAS28. Reliability: RAQoL and HAQ displayed good repeatability (ICC > 0.95) and internal consistency (Cronbach's alpha > 0.90). Responsiveness: SF-36 bodily pain scale and VAS pain were responsive to both improvement and deterioration.ConclusionAll instruments were valid measures for HRQOL in RA. The RAQoL and HAQ displayed the best reliability, while the SF-36 bodily pain scale and VAS pain were the most responsive. The choice of instrument should depend on the study objectives.

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