THE RAPID ASSESSMENT OF DISEASE-ACTIVITY IN RHEUMATOLOGY (RADAR) QUESTIONNAIRE - VALIDITY AND SENSITIVITY TO CHANGE OF A PATIENT SELF-REPORT MEASURE OF JOINT COUNT AND CLINICAL STATUS

Objective. This study documents the measurement properties of a brief, self-administered questionnaire of disease signs and symptoms in patients with rheumatoid arthritis. Methods. The Rapid Assessment of Disease Activity in Rheumatology (RADAR) questionnaire assesses joint pain/tenderness and clinical status. One hundred ninety-three pairs of RADAR forms were completed by 45 subjects and their assigned clinician evaluators. Results. Subject-clinician agreement (intraclass correlation coefficients [ICC]) for joint pain/tenderness and clinical status ranged from 0.52 to 0.87 (P = 0.0001), with 83% greater-than-or-equal-to 0.65. The ICC for change in joint scores over 6 months was 0.83 (P = 0.0001). Conclusion. The 2-page RADAR questionnaire produces valid estimates of joint count and clinical status that are sensitive to change.