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.