COMPARISON BETWEEN SELF-REPORT MEASURES AND CLINICAL OBSERVATIONS OF FUNCTIONAL DISABILITY IN ANKYLOSING-SPONDYLITIS, RHEUMATOID-ARTHRITIS AND FIBROMYALGIA

Objective. To study concordance between self-report measures and clini cal observations of functional disability in ankylosing spondylitis (A S), rheumatoid arthritis (RA), and fibromyalgia (FM). Methods. 35 pati ents with AS completed 9 selected items of the Functional Index questi onnaire, whereas 12 patients with RA and 13 with FM completed 7 select ed items of the Arthritis Impact Measurement Scales. Five days later, all 60 patients and 4 controls actually performed the selected activit ies, which were recorded on video. The tapes were assessed in random o rder by 12 observers (6 occupational therapists and 6 physicians). Bot h patients and observers indicated functional disability on a 10 cm vi sual analog scale (VAS). Results. Interobserver agreement was high (Cr onbach's alpha 0.98). All observers scored the 4 healthy controls as h aving no disability at all. Mean discordance scores (VAS patients minu s VAS observers) for the selected items were negligible in AS [-0.27 c m (p = 0.30)], moderate in RA [+1.10 cm (p = 0.06)] and high in FM [+2 .44 cm (p < 0.01)]. Conclusion. Discordance between self-report questi onnaires and observed functional disability is a feature most striking in FM. In validation of self-report questionnaires of functional disa bility the appropriate spectrum of rheumatological diagnoses should be considered.