Prevalence and Risk Factors of Spondyloarthritis Symptoms in a US-Based Multicenter Cohort of Patients with Inflammatory Bowel Disease.

Background/aim: Spondyloarthritis (SpA), the most common extra-intestinal manifestation of inflammatory bowel disease (IBD), is reported in up to 39% of patients with IBD. Despite this high prevalence, risk factors for developing SpA in patients with IBD are not well described. In this study, we aimed to determine the factors associated with SpA symptoms and their prevalence in an IBD cohort.

Methods: Two validated screening questionnaires for the detection of SpA in IBD (DETAIL = DETection of Arthritis in Inflammatory boweL diseases, IBIS-Q = IBD Identification of Spondyloarthritis Questionnaire) were administered to IBD patients without a prior diagnosis of SpA in six US academic medical centers. Demographic data, IBD characteristics, and medication history were recorded.

Results: Screening questionnaires were completed by 588 patients (220 ulcerative colitis, 349 Crohn's disease, 19 IBD-unclassified) with a median age 40 years (IQR 30 - 53) and median disease duration of 12 years (IQR 6 - 22). The number of positive screens was 130 (22%) for DETAIL, 196 (33%) for IBIS-Q and 204 (35%) for either DETAIL or IBIS-Q. Age, female sex, history of smoking, prior bowel surgery, and history of any biologic or targeted small molecule exposure were associated with a positive screen on univariate analysis (Table 1). After multivariate analysis, female sex (OR 2.03; 95% CI 1.41-2.93), older age (OR 1.02; 95% CI 1.01-1.04), history of smoking (OR 1.67; 95% CI 1.04-2.69), and history of any biologic or targeted small molecule exposure (OR 2.27; 95% CI 1.34-3.84) were independently associated with positive screens. Higher number of biologic exposures was associated with higher risk of positive screens, with the highest risk seen with three or more exposures (OR 3.25; 95% CI 1.75-6.03).

Conclusion: A substantial number of IBD patients screen positive for SpA symptoms, indicating a potentially high burden of undiagnosed illness. Factors associated with SpA symptoms include older age, female sex, and more severe disease (based on increased number advanced therapies or prior surgery), whereas IBD phenotype does not independently increase the risk of a positive SpA screen. Further studies are needed to confirm these findings and better characterize SpA in IBD.