AB1209 Usefulness of imagenology to differential diagnosis in patients with presumed seronegative rheumatoid arthritis and other arthropathies

Background It is difficult to make a differential diagnosis between seronegative RA and other inflammatory arthropathies. Many patients could be wrong diagnosed followed of expensives treatments. Objectives To assess the usefulness of X-rays of hands and feet (X-rays), Ultrasound (US) and Magnetic Resonance Imaging (MRI) to discard false positive diagnosis of seronegative RA from real-world evidence. Methods An analysis from medical records of patients with presumptive seronegative RA diagnosis reportedly seronegative for both rheumatoid factor and anti-cyclic citrullinated peptide antibodies and clinical criteria of RA, in the period between July 2016 and ; June of 2017 who were assesed by imagenology (X-rays, US or MRI) in a centre of rheumatoid arthritis to confirm diagnosis or discard it. Laboratory, and imagenology data was retrospectively analysed and multivariate analysis was performed to determinate the usefulness of imagenology. Results 360 patients were received in the centre with presumptive diagnosis of RA in the period, mean of age was 58 years, 80,9% females and 19,1% males. X-rays shows only 3,59% of patients with erosions, 38,6% were positive for Ostheoarthritis (OA), and 58,6% of patients without erosions. From patients without erosions, 36% were confirmed for RA and 13,4% for OA by US; on the other hand 37% was confirmed for RA and 20% for OA by MRI. A total of 94 patients (26,1%) had a final diagnosis of seronegative RA, while (261) patients 72,5% were confirmed for Osteoarthrosis,5 1,4% were classified in other arthropaties. Conclusions According with our findings the screening by imagenology is a useful tool with low cost to make a differential diagnosis of seronegative RA and other arthropaties. In order to improves outcomes through well-defined treatments and to save high cost treatments for pathologies with more precise diagnoses. Disclosure of Interest None declared