[Clinical evaluation and application of new ARA criteria for rheumatoid arthritis]

At the 51st American Rheumatism Association meeting, a new ARA criteria for rheumatoid arthritis (RA) was proposed. According to this criteria, both the sensitivity and the specificity have improved to 93% and 90%, respectively. We investigated the adequacy of this criteria by applying this to Japanese patients with RA and control subjects with rheumatic diseases, other than RA. By using new criteria the sensitivity was decreased from 89.6% to 85.3% and the specificity was increased from 82.7% to 92.8%. The factors for the decreased sensitivity of the new criteria were 1) morning stiffness which became more than 1 hour, 2) the number of swelling joints increased from one to three and 3) radiologic changes, which were restricted to the hand only. On the other hand, the factors for increased specificity were (1) morning stiffness, (2) deletion of criterion of joint pain and (3) joint swelling. According to the classification tree method, the sensitivity and the specificity were 96.3% and 90.0% respectively in this study. Continued nationwide study on this new criteria, whether this is applicable and useful to classify Japanese patients with RA is necessary.