SAT0643 Ultrasound abnormalities in wrist, mcp2 and mtp5 are most discriminative in predicting arthritis development in seropositive arthralgia patients

Background Seropositive arthralgia patients are at risk of developing rheumatoid arthritis (RA). Ultrasound (US) might be used to further predict which seropositive individuals will progress to RA. However, the value of US in the prediction of RA is still a point of debate, mainly due to the use of different scoring systems and compositions of joints in US protocols in literature. Objectives To investigate which joints are most discriminative in predicting arthritis development in seropositive arthralgia patients. Methods We included 174 seropositive patients with arthralgia, but without clinical arthritis. US was performed at baseline in 16 joints: bilateral metacarpal phalangeal (MCP) 2 and 3, proximal interphalangeal (PIP) 2 and 3, wrist and metatarsal phalangeal (MTP) joints 2, 3 and 5. Images were scored for grey-scale (GS) synovitis and Power Doppler (PD) on a scale of 0–3. Grades≥2 for GS synovitis and grades≥1 for PD were regarded as abnormal. Clinical arthritis development was assessed in any of 44 joints during yearly follow-up or during an unscheduled visit in case of progression of symptoms. Patients were followed until clinical arthritis development or for a maximum of 5 years. Results In a total of 2784 joints that were imaged, 112 showed GS synovitis and 14 PD. The majority of GS synovitis was present in MTP2 and MTP3 joints (56 (50%) and 32 (29%), respectively), followed by wrists (15 (13%)), MCP3 (4 (4%)), MTP5 (3 (3%)), MCP2 (2 (2%)) and none in PIPs. Out of 14 joints with PD, 7 were wrists, 3 MTP5, 2 MCP2 and 2 PIP3. Fifty-one (29%) of the patients developed clinical arthritis in at least one joint after a median follow-up of 12 (interquartile range 6–23) months. For GS synovitis, the wrist, MCP2 and MTP5 were most discriminative in predicting clinical arthritis development (12/15 (80%) of patients with GS synovitis in wrist developed clinical arthritis, 3/3 (100%) in MTP5 and 2/2 (100%) in MCP2). MTP2 and 3 were least discriminative ( Conclusions Wrist, MCP2 and MTP5 joints (although numbers were small) showed the highest predictive value for development of clinical arthritis in any of 44 joints. Although most GS synovitis was observed in MTP2 and 3, predictive value of MTP2 and 3 joints for development of clinical arthritis was low. These results indicate that the choice of joints in the US protocol may influence the predictive value of ultrasound in predicting clinical arthritis development in seropositive arthralgia patients. Disclosure of Interest None declared