Self-administered joint counts in rheumatoid arthritis: Comparison with standard joint counts

Objective. To test the reliability and validity of a self-administered 36 j oint count developed after the Rapid Assessment of Disease Activity in Rheu matology (RADAR) questionnaire for assessing pain/tenderness. Methods. Two self-administered formats (mannequin and text) were evaluated in 60 patients with rheumatoid arthritis (RA). Reliability between both for mats was tested by Spearman rank correlation. Criterion validity/accuracy w as tested by Spearman correlation coefficient between each self-report form at and a joint count performed by a physician. Construct validity was ascer tained by correlation of each format with other variables of disease activi ty. Results. Reliability between the 2 formats was high (R = 0.94). Correlation s between each format and the physician's joint count were also high (R = 0 .77 for mannequin, 0.75 for text). Patients consistently rated their joint pain/tenderness higher than the physician (means 29, 27, and 12 for text, m annequin, and physician, respectively; p < 0.01). Construct validity of the text, mannequin, and physician formats compared with the modified Health A ssessment Questionnaire showed R = 0.61, 0.65, 0.63; with Steinbrocker func tional class R = 0.91, 0.46, 0.56; with pain R = 0.59, 0.61, 0.62; with glo bal evaluation R = 0.66, 0.71, 0.84; and with morning stiffness R = 0.64, 0 .59, 0.60, respectively. Conclusion. Although both self-administered formats exhibited adequate reli ability and construct validity a systematic difference between patient and physician/trained assistant performed joint counts was observed, with patie nts consistently rating their pain/tenderness higher. We thus do not believ e they can replace standard physician/trained assistant evaluation in obtai ning clinical research data in rheumatology.