AB0719 PREVALENCE OF UNDIAGNOSED AXIAL SPONDYLOARTHRITIS IN PATIENTS WITH INFLAMMATORY BOWEL DISEASE: A SYSTEMATIC LITERATURE REVIEWAND PRIMARY RESEARCH STUDY
Authors: Jobie Evans, Mark Sapsford, Tim Raine, Scott Mcdonald, Miles Parkes, Gavin Clunie, Deepak Jadon
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background:</h3> Axial spondyloarthritis (axSpA) encompasses psoriatic arthritis with axial disease, ankylosing spondylitis and non-radiological axSpA. Patients with axSpA have a high burden of inflammatory bowel disease (IBD) but few studies have investigated the proportion of IBD cases that have undiagnosed axSpA. Untreated axSpA could have a significant impact on the general health and quality of life of patients; therefore early diagnosis and treatment is crucial[1]. <h3>Objectives:</h3> This systematic literature review (SLR) aimed to identify the prevalence of undiagnosed axSpA in IBD cases based on cross-sectional imaging (MRI and CT scans) of the axial skeleton from published data. <h3>Methods:</h3> This SLR was performed in keeping with MOOSE guidelines for observational studies. Original articles in all languages from 1990-2018 were retrieved from PubMed, Embase and Cochrane databases. Article reference lists were checked for further literature. Rheumatology conference (ACR, EULAR, GRAPPA, BSR, Gent Spondyloarthritis) abstract lists from 2012-2018 were reviewed and authors contacted for any additional unpublished data. All abstracts were reviewed by two authors to determine eligibility for inclusion. <h3>Results:</h3> Twenty observational studies were identified: twelve published papers and eight abstracts. Thirteen studies assessed the prevalence of CT-sacroiliitis in IBD cases, two used magnetic resonance enterography (MRE) imaging and five used MRI imaging. The studies included a variety of patient demographics and IBD types. Sample sizes ranged between 25-1247 patients. Eleven studies included 2 independent radiology readers. The presence of inflammatory back pain was assessed in 7/20 studies, 5/20 included a control group and only 3/20 included a clinical rheumatology assessment. Thirteen studies used IBD imaging to assess for sacroiliitis compared to seven using dedicated MRI or CT imaging of the sacroiliac joints. The prevalence of sacroiliitis ranged from 2.2% to 68%. Eleven studies included patients with Crohns disease (average sacroiliitis prevalence 18.6%) and Ulcerative colitis (average sacroiliitis prevalence 17.4%), with 7/11 studies stating no significant difference in the prevalence of sacroiliitis between the two groups. Four studies identified an association of sacroiliitis with increased disease duration, two with increasing age and only one with IBD location. <h3>Conclusion:</h3> From these studies, it appears that axSpA may affect a substantial number of patients with IBD and is likely to be significantly underdiagnosed. Cross-sectional imaging intended for the assessment of IBD can be utilised to screen for the presence of axSpA, perhaps even before the onset of musculoskeletal symptoms. Such patients could then be triaged for detailed rheumatological assessment. This review highlights the sparsity of data on the prevalence of axSpA in IBD cases. Few studies have included a clinical rheumatological assessment and just over half assessed for any potential difference in the prevalence of sacroiliitis in the Crohn's disease (CD) and Ulcerative colitis groups. This review has informed our prospective cross-sectional single-centre observational study, due to start in February 2019. We will assess the sensitivity and specificity of MRE as a screening tool for axSpA in a cohort of 600 CD cases, using clinical assessment and a dedicated axial MRI scan as the gold standard. <h3>References</h3> [1] Ozgul, a., et al., Effect of ankylosing spondylitis on health-related quality of life and different aspects of social life in young patients. Clin Rheumatol, 2006. 25(2): p.168-74. <h3>Disclosure of interests:</h3> Jobie Evans Grant/research support from: I am currently working on a MD research project looking at the use of magnetic resonance enterography imaging as a screening tool for axial spondyloarthritis in patients with Crohn's disease. This study is commercially funded by Merck, Sharp and Dohme corporation (MSD)., Mark Sapsford: None declared, Tim Raine: None declared, Scott McDonald: None declared, Miles Parkes: None declared, Gavin Clunie: None declared, Deepak Jadon: None declared