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

Background In IBD patients, 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 MRI-detected involvement of the spine and sacroiliac joints (SIJs) in early IBD. Methods Newly diagnosed IBD patients 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 (ax)SpA. Results Of 110 patients (ulcerative colitis: 70, Crohn’s disease: 40, mean age 42 years, 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 ASAS 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 UC and CD patients. Conclusion One-in-six newly diagnosed IBD patients 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.