Background Spondyloarthropathy (SpA) is an important extraintestinal manifestation of inflammatory bowel disease (IBD). The spectrum and incidence of this form of arthritis are not well studied in a defined population base.
Objectives We aimed to assess the cumulative incidence and clinical spectrum of SpA for the first time in a population-based cohort of patients with IBD. Also, we aimed to compare the cumulative incidence of SpA in ulcerative colitis (UC) to that of Crohn’s disease (CD).
Methods The medical records of a population-based cohort of Olmsted County, MN residents diagnosed with IBD from 1970 through 2004 were reviewed. Patients were followed longitudinally until moving from Olmsted County, death, or June 30, 2011. We recorded data on musculoskeletal symptoms and disease, and used the European Spondyloarthropathy Study Group and New York criteria to identify patients with SpA. The cumulative incidence of SpA subsequent to IBD diagnosis was estimated using Kaplan-Meier methods
Results The cohort included 676 patients with IBD (Crohn’s disease [CD] n=311; ulcerative colitis [UC] n=365), of which 45.6% were women. The median age at diagnosis of IBD was 33.1 years (range 1-91). Prior to IBD diagnosis, the prevalence of spondyloarthropathy was 1.0% (95% confidence interval [CI], 0.4%>2.1%). The overall cumulative incidence of a diagnosis of spondyloarthropathy after an established diagnosis of IBD was 2.3% (95% CI, 1.1%>3.5%) at 10 years, 4.2% (2.3%>6.1%) at 20 years, and 4.9% (3.5%>10.3%) at 30 years. The 10, 20 and 30 year rates respectively for CD were 2.6%, 6.1%, and 9.8%, and for UC 1.9%, 2.8% and 4.9%. The overall 10-year cumulative incidence of ankylosing spondylitis for all IBD was 0.2% (0-0.5%) and 20-year cumulative incidence was 0.7% (0-1.6%). Sacroiliitis, oligoarthritis and polyarthritis were observed in 1.6%, 3.1% and 1.3% of patients in the post-IBD diagnosis period, respectively.
Conclusions We have for the first time defined the actual cumulative incidence of SpA in IBD using complete medical record information in a population-based cohort. The cumulative incidence of all forms of SpA increased to about one in 50 patients by 10 years from IBD diagnosis and one in 20 patients by 30 years from IBD diagnosis. The rate of SpA in UC patients is about half of the incidence rate seen over the same time period in our CD cohort. SpA is known to be associated with IBD and, therefore, clinicians must be cognizant of this extraintestinal manifestation when caring for a patient with IBD.
Disclosure of Interest None Declared