- All RA patients in this study will satisfy the American Rheumatism Association 1987 revised criteria for the diagnosis of RA. Active disease will be defined by the presence of at least 3 swollen joints, ≥6 tender or painful joints and at least 2 of the following features: duration of morning stiffness 60 minutes, erythrocyte sedimentation rate (ESR) ≥28 mm/hour and serum CRP level of at least 2.0 mg/dl (26).