To analyze a patient self-report joint count from the Rheumatoid Arthritis Disease Activity Index (RADAI) on a Multidimensional Health Assessment Questionnaire (MDHAQ) in a cohort of consecutive patients seen in usual rheumatology care with rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), osteoarthritis (OA), psoriatic arthritis (PsA), and gout.
Each patient completed an MDHAQ, which included a RADAI, at each visit in one usual care setting. In order to include a physician measure, a random visit at which there was a recorded physician global estimate was selected for each of 465 patients (174 patients with RA, 75 with SLE, 113 with OA, 53 with PsA, and 50 patients with gout). The RADAI was analyzed for total scores (range 0–48), number of involved joint groups (range 0–16), and each specific joint group, and then compared in the 5 diagnostic groups to one another and to other MDHAQ measures and the Routine Assessment of Patient Index Data 3 (RAPID3).
In patients with RA, SLE, OA, PsA, and gout, mean RADAI scores (range 0–48) were 12.4, 6.5, 10.1, 6.7, and 2.7, respectively. The mean numbers of involved joint groups (range 0–16) were 6.9, 3.8, 4.8, 4.5, and 1.7, respectively, and the median numbers were 6, 2, 4, 4, and 1, respectively. RADAI scores were correlated significantly with the physician global estimate, except in SLE, and at higher levels with the MDHAQ and RAPID3 scores in all diagnostic groups.
The RADAI self-report joint counts can be used to record self-report involvement of specific joints and joint groups in patients with SLE, OA, PsA, and gout, with minimal effort on the part of the rheumatologist.