P813 Occurrence, disease course and prognosis of perianal Crohn’s disease in a Danish population-based inception cohort—a 10-year follow-up study

Abstract

Background: Perianal complications in patients with Crohn's disease (CD) are common and associated with a relapsing-remitting course with a negative impact on the patients' quality of life. Data on the long-term disease course in the era of biological therapy are limited. In this population-based cohort study we sought to investigate the occurrence, clinical risk factors and disease course of perianal CD in the era of biologic therapy. Method(s): A total of 213 CD patients diagnosed between January 1, 2003-December 31, 2004 were included in a prospective population-based inception cohort. Clinical data were retrieved from medical records and data on surgery, cancer, and death were crosschecked with register data from national health administrative databases until December 2016 ensuring complete follow-up. Perianal CD was defined as the occurrence of a perianal fistula and/or abscess. Associations between primary endpoints (surgery and hospitalisation) and covariates were analysed by Cox regression analysis. Result(s): A total of 48 (25%) patients developed perianal CD after ten years. Colonic disease location (HR 1.99, 95% confidence interval (CI) 1.01-3.92) and penetrating behaviour (HR 5.65, 95% CI 2.65-12.03) were identified as predictors of perianal CD. The cumulative risk of undergoing perianal surgery and abdominal surgery after 10 years was 67% and 51%, respectively. Patients with perianal CD had a significantly higher rate of intestinal resections (HR 3.92, 95% CI 1.86-8.67). During a follow-up of 10 years, patients with perianal CD were hospitalised for 77.5 (interquartile range (IQR) 39.5-153.5) days in median compared with 46 (IQR 25-84) days in patients without. Total days of hospitalisation was significantly higher for patients with perianal CD (HR 1.01, 95% CI 1.004-1.011). (Figure presented) Conclusion(s): The incidence of perianal CD seems to have decreased compared with studies in earlier eras, which may be caused by an increased usage of biologic agents. However, the rate of both perianal and abdominal surgery remains high. We found a higher risk of intestinal resection and hospitalisation in patients with perianal CD suggesting a more severe and protracted course. These findings underline the importance of early identification of patients at risk of developing perianal CD who might benefit from early introduction of aggressive therapy.