S1771 Systemic Vasculitis Patterns Among Hospitalized Patients With Inflammatory Bowel Disease in the United States

Introduction: Inflammatory bowel disease (IBD) is associated with extraintestinal manifestations, but the association with systemic vasculitides remains poorly defined. This study aims to evaluate the prevalence of systemic vasculitis in hospitalized patients with Crohn’s disease (CD) and ulcerative colitis (UC), compared to non-IBD admissions. Methods: We analyzed 2018–2022 data from the National Inpatient Sample, identifying hospitalizations with systemic vasculitides using International Classification of Diseases-10 codes (including Takayasu arteritis, granulomatosis with polyangiitis [GPA], eosinophilic granulomatosis with polyangiitis, microscopic polyangiitis, giant cell arteritis, polyarteritis nodosa, cryoglobulinemia, and hypersensitivity vasculitis). CD and UC were identified as secondary diagnoses. Weighted cross-tabulations were used to estimate prevalence. Multivariable Poisson regression was performed to calculate adjusted prevalence ratios (APRs), adjusting for demographic and clinical covariates. Analyses were conducted using STATA v18. Results: Systemic vasculitis was rare overall, but more frequent among patients with IBD: 0.224% in UC, 0.153% in CD, vs 0.124% in non-IBD admissions (P < 0.001). After adjustment, UC hospitalizations had a 37% higher vasculitis prevalence than CD (APR 1.37; 95% CI: 1.15–1.63). Increased vasculitis prevalence was independently associated with female sex (APR 1.36), Black race (APR 2.20), and age >65 years (APR 2.80). In contrast, Medicaid insurance and smoking were associated with lower odds of vasculitis (APR 0.49 and 0.81, respectively). GPA and Takayasu arteritis accounted for the majority of vasculitis cases: GPA affected 0.064% of UC and 0.040% of CD discharges (P < 0.001), while Takayasu arteritis was noted in 0.015% of CD and 0.013% of UC admissions vs 0.004% in non-IBD admissions (P < 0.001). Other vasculitides were present in < 0.01% of cases without significant differences. Conclusion: Systemic vasculitides are uncommon but significantly more prevalent among hospitalized patients with IBD, particularly those with UC. Female sex, Black race, and older age are associated with increased risk. GPA and Takayasu arteritis represent the most common vasculitic conditions in this population. Further studies are warranted to elucidate underlying mechanisms and implications for IBD management.