THU0375 CLINICAL FEATURES OF AXIAL SPONDYLOARTHRITIS PATIENTS DIAGNOSED IN PERIPHERAL VERSUS AN ACADEMIC HOSPITAL
Authors: Ann-Sophie De Craemer, Thomas Renson, Philippe Carron, Peggy Jacques, Jan Lenaerts, Lieve Gyselbrecht, Rik Joos, Filip van den Bosch, Dirk Elewaut
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Diagnosis of axial spondyloarthritis (axSpA) often relies on a positive magnetic resonance image of the sacroiliac joints (MRI-SIJ). However, pitfalls in interpretation of MRI-SIJ were recently acknowledged (1). Thus reader’s expertise might be a source of heterogeneity in patient populations diagnosed with non-radiographic axSpA. <h3>Objectives</h3> We compared clinical characteristics of axSpA patients diagnosed in peripheral hospitals (MRI evaluation by local experts) versus an academic hospital (MRI central reading by trained radiologists and rheumatologists). <h3>Methods</h3> Patients originate from the Be-Giant cohort, a Belgian nationwide observational registry of axSpA patients diagnosed by expert opinion. Included patients fulfill the Assessment of SpondyloArthritis international Society (ASAS) classification criteria for axSpA and are anti-TNF-α naïve prior to inclusion. Patient enrollment started in 2010 and 2012 at the outpatient clinic of 1 academic and 7 peripheral hospitals respectively. Patients were free to visit a rheumatologist of their choice without necessity for referral by a general practitioner. <h3>Results</h3> By January 2019, 291 axSpA patients were included. Table 1 presents demographic and clinical characteristics according to the diagnostic echelon. The patient fraction fulfilling the imaging arm of the ASAS classification criteria was similar in both settings (75,4% vs. 88,7%, p = 0,21). However, because of a higher HLA B27 positivity rate in patients diagnosed in an academic versus peripheral hospitals (73,5% vs. 57,4%, p = 0,01), a significantly higher fraction of patients fulfilled both the clinical and imaging arm in the former diagnostic setting (63,0% vs. 37,7%, p = 0,01). <h3>Conclusion</h3> Patients diagnosed with axSpA in peripheral versus an academic hospital generally show similar demographic and clinical characteristics. In an academic center, patients diagnosed with axSpA are more likely to be HLA B27 positive and to fulfill both ASAS classification arms, indicating that rheumatologists in peripheral hospitals seem to assign more value to MRI findings compared to HLA B27 status in the diagnostic process. <h3>References</h3> [1] Varkas G, de Hooge M, Renson T, De Mits S, Carron P, Jacques P, et al. Effect of mechanical stress on magnetic resonance imaging of the sacroiliac joints: assessment of military recruits by magnetic resonance imaging study. Rheumatology (Oxford). 2018;57(3):508-13. <h3>Abstract THU0375 – Table 1</h3> Continuous variables: mean (SD); other: counts(%). <h3>Disclosure of Interests</h3> Ann-Sophie De Craemer: None declared, Thomas Renson: None declared, Philippe Carron: None declared, Peggy Jacques: None declared, Jan Lenaerts: None declared, Lieve Gyselbrecht: None declared, Rik Joos: None declared, Filip van den Bosch Consultant for: AbbVie, BMS, Galapagos, Janssen, Lilly, Merck, Novartis, Pfizer and UCB, Speakers bureau: AbbVie, BMS, Janssen, Lilly, Merck, Novartis, Pfizer and UCB., Dirk Elewaut: None declared