Pos0520 Inflammatory Bowel Disease in Axial Spondyloarthritis Patients. Is There Any Specific Clinical Picture?

Background: Inflammatory bowel disease (IBD), including ulcerative colitis (UC) and Crohn's disease (CD), affects 5–10% of axial spondyloarthritis (axSpA) patients. Prior data suggests axSpA patients with IBD may have more severe disease and lower HLA-B27 prevalence. Yet, little is known about potential distinctions in axSpA with IBD compared to those without IBD. Objectives: To investigate the clinical characteristics and radiographic differences between patients with axSpA with and without concurrent IBD. Methods: This multicenter, observational, cross-sectional study included patients meeting European Spondyloarthropathy Study Group criteria from the Registry of Spondyloarthritis of Spanish Rheumatology (REGISPONSER) and Ibero-American Registry of Spondyloarthropathies (RESPONDIA) registries. Characteristics and disease burden were compared between patients with and without IBD. Multivariate logistic regression identified factors independently associated with IBD presence in patients with radiographic axSpA (r-axSpA) Results: We included a total of 2,766 patients with r-axSpA (1254 from REGISPONSER and 1512 from RESPONDIA), among whom 142 patients (5.13%) presented with concomitant IBD. AxSpA patients with concurrent IBD were less frequently male, had a lower prevalence of HLA-B27 positivity, experienced a lower prolonged diagnostic delay, had a lower frequency of enthesitis, and received more commonly intensified treatment compared to those without IBD (Table 1). In terms of structural damage, the BASRI score for the sacroiliac joints, cervical spine, and lumbar spine was lower in patients with r-axSpA and IBD than in those without IBD (Table 1). Conversely, no statistically significant differences were observed between the groups in disease activity as evaluated by the BASDAI and ASDAS. In the multivariable analysis, the presence of IBD was significantly associated with a lower prevalence of HLA-B27 and enthesitis, with odds ratios (OR) of 0.32 (CI95% 0.20 - 0.52) and 0.58 (CI95% 0.33 - 0.97), respectively. Furthermore, structural damage in sacroiliac joints (BASRI) was significantly decreased in patients with IBD, with an OR of 0.79 (CI95% 0.64 - 0.99). Conclusion: The presence of IBD in r-axSpA is associated with less HLA-B27 positivity, less enthesitis and less radiographic damage in this large population study. REFERENCES: NIL. Acknowledgements: NIL. Disclosure of Interests: Montserrat Cabanillas Paredes: None declared, Ignacio Gómez-García: None declared, Mireia Moreno Not related to the study., Not related to the study, Marta Arévalo Not realted to the study, Jordi Gratacós Not related to the study, Not related to the study, Not related to the study, Eduardo Collantes-Estevez Not related to the study, No related to the study, Not related to the study, Clementina López-Medina No related to the study, No related to the study, No related to the study, María LLop Vilaltella No related to the study., No related to the study.