IDENTIFICATION OF JOINT LOCATIONS IN AN EARLY RHEUMATOID ARTHRITIS COHORT AS A CHARACTERISTIC OF DISEASE SEVERITY. DATA FROM THE ERA-UCLOUVAIN BRUSSELS COHORT

Background Early RA patients (ERA pts) often present with different areas of joint involvement, but limited data exist to identify which specific joint locations may be indicative of greater disease severity1. Objectives This analysis investigated the baseline (BL) prevalence of swelling in individual joint locations and their possible association with disease characteristics and prognostic factors in a cohort of ERA pts. Methods This analysis was based on data from the ERA UCLouvain Brussels cohort in which patients were included according the ACR/EULAR 2010 criteria, naïve to DMARDs and followed in our daily clinic. The physician assessed prevalence of baseline individual swollen joint status (present, absent) through a physical examination. The joint count includes 44 joints. Similarly, all patient and RA characteristics were analyzed.The association between BL swelling and disease characteristics was investigated for each individual joints. Results 453 ERA pts were analyzed, BL swelling was most frequently observed in the wrist (71.1%) followed by IPP 3 and 2 joints (52.5 and 50.1%) (Table 1). MTP4 et 5 was more present in younger and MCP 2-4 in older pt *. BL swelling in the large size joint (knee, elbow, shoulder and ankle), in the medium size joint (wrist) and the small size joint (only MCP3, IPP 1, 2 and MTP5) was highly associated with higher DAS28 (CRP) *. Pts with BL swelling MCP1, 3, 4; MTP 1,2, 5 was associated with erosive disease*. In contrast, swelling of the knee was correlated with non erosive and also seronegative RA*. Swelling of many joints locations (knee, shoulder, ankle, MCP 1-5, MTP1, 5 and IPP 1, 2) were correlated significantly with a higher HAQ*. Only swelling of MTP1, 2, 5 was associated with the presence of ACPA antibodies*. No difference was observed for smoking habits and gender. (*) - p≤0.001. Conclusion In our cohort of ERA, small joints swelling was associated with erosive and seropositive RA (only MTP). Swelling of the large joint and the wrist seems to be associated with higher disease activity. In ERA, a difference in joint location presentation may identify pts with poor pronostic factors to be eligible for an intensive treatment or a personalized treatment approach. Further analysis are planned to analyze the correlation with erosion in each joint location and response to Methotrexate