Peripheral arthritis in patients with long-term inflammatory bowel disease. Results from 20 years of follow-up in the IBSEN study

<b>Objectives:</b> Peripheral arthritis and related musculoskeletal manifestations, often classified as peripheral spondyloarthritis, are frequently seen in patients with inflammatory bowel disease (IBD). Few long-term studies have reported on the prevalence of these conditions. The aim of this study was to determine the prevalence of IBD-related peripheral arthritis and peripheral spondyloarthritis in IBD patients during 20 years of disease course, and to assess whether these conditions were associated with the intestinal IBD severity and activity. <b>Materials and methods:</b> In an inception cohort (the IBSEN study), IBD patients were followed prospectively for 20 years. At the 5 year follow-up the patients underwent a rheumatological examination and at the 20 year follow-up they completed a questionnaire with identical questions. When peripheral arthritis was characteristic and not explained by other specific diagnoses, it was defined as IBD-related peripheral arthritis. The Assessment of Spondyloarthritis International Society criteria were used to define peripheral spondyloarthritis, including patients with peripheral arthritis, enthesitis and/or dactylitis. <b>Results:</b> After 20 years of follow-up, 441 patients were included (296 ulcerative colitis and 145 Crohn’s disease). The prevalence of IBD-related peripheral arthritis was 17.2% and peripheral spondyloarthritis 27.9% during the disease course. IBD severity and activity were not different between those with a history of IBD-related peripheral arthritis or peripheral spondyloarthritis and those without. A higher proportion of women had IBD-related peripheral arthritis and peripheral spondyloarthritis. <b>Conclusion:</b> During 20 years of disease course, more than every sixth patient had suffered from IBD-related peripheral arthritis and every fourth from peripheral spondyloarthritis.