The new ACR/EULAR criteria for rheumatoid arthritis can identify patients with same disease activity but less damage by ultrasound.

OBJECTIVE We aimed to compare the ultrasound findings of patients fulfilling the 1987 ACR [OLD-rheumatoid arthritis (RA)] and the new ACR/EULAR (NEW-RA) classification criteria to examine the impact of the new criteria on disease characteristics, particularly disease duration. MATERIAL AND METHODS A total of 2730 hands, wrists, elbows, knees, ankles, and foot joints of 105 consecutive patients with inflammatory arthritis, i.e., 82 patients fulfilling the RA criteria (60 patients, OLD-RA; 22 patients, NEW-RA alone) and 23 patients with undifferentiated arthritis, were scanned using ultrasound. Synovitis, erosions, and power Doppler (PD) findings were scored using a scale of 0-3 and scores form each joint were added up to calculate synovitis, PD and erosion scores for each patient. RESULTS OLD-RA and NEW-RA patients had similar swollen joint count, tender joint count, acute-phase response, patient global, and disease activity assessment 28 scores. The disease duration was longer in OLD-RA patients [30 (3-179) months] than in NEW-RA patients [16 (0-45) months; p=0.009]. Both the groups had similar synovitis and PD scores, whereas erosion scores were higher in OLD-RA patients than in NEW-RA patients (p=0.009). Patients with undifferentiated arthritis were older than those with RA and had fewer swollen joints than NEW-RA patients [0 (0-4) vs. 2 (0-9); p=0.017]. All other disease activity parameters were similar in both NEW-RA and OLD-RA patients. Both the synovitis (p=0.006) and erosion (p=0.007) scores were lower in patients with undifferentiated arthritis than in OLD-RA patients, despite the scores being similar to those in NEW-RA patients. CONCLUSION The new ACR/EULAR RA criteria enabled the classification of patients with similar disease activity (by clinical assessment and ultrasound) but with less damage. A similar disease activity should ensure suitability for an intervention, and a shorter duration and less damage should improve the outcome with patient benefit.