THU0376 THE VALUE OF SACROILIAC JOINT RADIOGRAPHS IN THE EARLY SPONDYLOARTHRITIS ESPERANZA COHORT
Authors: Eugenio de Miguel, Beatriz Joven-Ibáñez, Eva Galindez, Claudia Urrego-Laurín, Maria Luz García-Vivar, Cristina Fernández-Carballido, Jose Francisco Garcia Llorente, María del Carmen Castro Villegas, Carolina Tornero, Xavier Juanola-Roura
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> X-Ray sacroiliitis is the cornerstone in the diagnosis of the ankylosing spondylitis (AS). It is clear that the presence of sacroiliitis is a specific lesion in long standing AS, but little evidence exists on the reliability of this image technique in early axial spondyloarthritis (axSpA), which associates with reduced structural damage. This is relevant because some rheumatologists and pharmacological authorities feel more confident with the diagnosis of AS rather than with non radiographic axial spondyloarthritis (nr-axSpA) forms. On the other hand, according to various research studies, clinicians are subject to potential bias when interpreting radiographs, influenced by their pretest clinical judgment. <h3>Objectives</h3> The aim of this study is to determine the value of X-Ray sacroiliitis in the early diagnosis of axSpA. <h3>Methods</h3> This study included 290 radiographs of the SI joints from patients of the Esperanza early spondyloarthritis cohort. Nine readers, blinded for the diagnosis, participated in the reliability exercise, all of them experienced rheumatologists and members of the Spanish spondiloarthritis working group (GRESSER). Patients with axSpa were classified as having AS if the radiographic criteria of the modified NY criteria (presence of radiographic changes in the SIJ of at least grade II bilaterally or at least grade III unilaterally) were fulfilled. The gold standard was the categorical opinion of at least five of the expert readers. For the statistical analysis, the Chi-square and Kappa tests were performed. <h3>Results</h3> The radiographic diagnosis, sensitivity, specificity, likelihood ratio, grade of agreement and mean K values compared to gold standard are showed in table 1. The concordance Kappa test was highly variable among the readers, ranging from fair to excellent. The agreement with the gold standard varied from 68 to 94% and the sensitivity and specifity, from 50-100% and 64-96%, respectively. Additionally, the number of AS was 61, with an inter-reader variability rate of 31 to 138. Larger discrepancies were observed when assessing sacroiliitis grade 2. <h3>Conclusion</h3> The diagnosis of AS in early axSpa is characterized by a marked variability. At least in doubtful cases, a second central evaluation performed by highly qualified experts should be advisable. <h3>Disclosure of Interests</h3> Eugenio de Miguel: None declared, Beatriz Joven-Ibáñez Speakers bureau: Celgene, Novartis, MSD, Pfizer, AbbVie, and Janssen, Eva Galindez: None declared, Claudia Urrego-Laurín: None declared, Maria Luz García-Vivar: None declared, Cristina Fernández-Carballido: None declared, Jose Francisco Garcia LLorente: None declared, María del Carmen Castro Villegas Paid instructor for: MSD, Abbvie, Pfizer, Janssen, Lilly, Roche, Carolina Tornero: None declared, Xavier Juanola-Roura: None declared