Spine and Sacroiliac Joint Involvement in Newly Diagnosed Patients With Inflammatory Bowel Disease: Clinical and MRI Findings From a Population-Based Cohort

INTRODUCTION: In patients with inflammatory bowel disease (IBD), co-occurring spondyloarthritis (SpA) leads to poorer outcomes and impaired quality of life, highlighting the importance of early detection and effective treatment. This is the first study to assess the prevalence and distribution of axial symptoms and magnetic resonance imaging (MRI)-detected involvement of the spine and sacroiliac joints (SIJs) in early IBD. METHODS: Newly diagnosed patients with IBD from a prospective, population-based cohort were consecutively recruited. Rheumatological interview, clinical, ultrasound, and MRI assessment for SIJ and spine inflammatory and structural lesions were made using validated scoring methods and consensus definitions of axial SpA (axSpA). RESULTS: Of 110 patients (ulcerative colitis: 70, Crohn's disease: 40, mean age of 42 years, and 40% male), 48 (44.9%) reported back and/or buttock pain, and 10 (9.1%) had inflammatory back pain. Seventeen (16.7%) patients had MRI findings indicative of axSpA; only 10 of these patients had axial symptoms. Inflammatory MRI lesions were present in SIJs and the spine of 27 (26.5%) and 30 (30.3%) patients, respectively. The Assessment of SpondyloArthritis International Society classification criteria for axSpA were met in 11 (10%) cases. MRI findings typical of axSpA were associated with peripheral joint and entheseal inflammation detected by ultrasound ( P = 0.04). No differences in clinical or imaging findings were found between patients with ulcerative colitis and Crohn's disease. DISCUSSION: One-in-6 newly diagnosed patients with IBD had MRI findings indicative of axSpA. As 40% of these patients were asymptomatic, this suggests that axSpA is underdiagnosed in early IBD. Multidisciplinary collaboration is essential to ensure early detection of axial inflammation and to enable optimal therapy preventing future structural damage and disability.