P572 Coexisting Inflammatory bowel disease and Ankylosing spondylitis: Management and clinical outcomes

Abstract

Background Ankylosing spondylitis (AS), which occurs in about 10% of inflammatory bowel disease (IBD) patients, is more common in Crohn's disease and does not correlate with bowel activity. The occurrence of IBD in patients with AS is 5-10%. We aimed to investigate the patterns of treatment modifications following newly diagnosed AS in patients with IBD or a new IBD diagnosis in patients with AS. Methods This is a retrospective observational study that included patients with coexisting IBD and AS that were followed simultaneously by the gastroenterology and the rheumatology departments of the Sheba Medical Center. Patients with a follow-up duration of at least 3 months since the second diagnosis were included. Results The cohort consisted of 68 patients, 41 with a first diagnosis of IBD (fIBD-group) and 27 with a first diagnosis of AS (fAS-group). Patients in the fAS-group were younger (median age of 36 years, inter quartile range (IQR) 25-48 vs. 43 years IQR 35-56, p=0.043), had more Crohn's disease (92.6% vs. 68.3%, p=0.016), had a shorter interval up to the second diagnosis (median of 3 years, IQR 1-6 vs. 6 years, IQR 2-11.5, p=0.03), and had an increased rate of past/current biologic treatment (81% vs. 51%, p=0.019) compared with the fIBD-group. Therapy modifications rates were 78% in the fIBD-group and 96% in the fAS-group as presented in Figure 1. The most common modification for the fIBD-group was initiation of biologic therapy in 18/32 patients (Adalimumab 44%, Infliximab 33%, Golimumab 5.75%, Etanercept 5.75%, Certolizumab pegol 5.75%, Ustekinumab 5.75%). In the fAS-group, switching biologic agent to Adalimumab or Infliximab (42%) and ceasing NSAIDs (27%) were the most common. At 1-year follow-up there were no significant differences in clinical outcomes (treatment failure, surgery/hospitalization, clinical remission) between fIBD and fAS groups. However, patients in both groups with treatment modifications, had a trend for higher rate of IBD clinical remission than patients without (72% vs. 40%, p=0.066). No difference was found in AS clinical outcome. Conclusion Treatment modifications are common among newly coexisting IBD and AS patients, preferably biologic drug modifications. These modifications may contribute to IBD clinical remission.