P238 Natural history of perianal fistulizing Crohn’s disease in the Swiss IBD cohort

N. Aslan1, J.B. Rossel2, V. Pittet2, E. Safroneeva3, S. Godat1, S. Vavricka4,5, T. Greuter5, L. Biedermann5, A. Straumann5,6, M. Scharl5, M. Schaad7, D. Hahnloser8, G. Rogler5, A. Schoepfer1, Swiss IBD Cohort Study Group

1Division of Gastroenterology and Hepatology, Centre Hospitalier Universitaire Vaudois CHUV and University of Lausanne, Lausanne, Switzerland, 2Institute of Social and Preventive Medicine IUMSP, Lausanne University Hospital, Lausanne, Switzerland, 3Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland, 4Vulkanplatz, Center for Gastroenterology and Hepatology, Zurich, Switzerland, 5Department of Gastroenterology and Hepatology, University Hospital Zurich, Zurich, Switzerland, 6Pediatrician Römerhof, Swiss EoE Center, Olten, Switzerland, 7Hôpital Riviera-Chablais, Department of Internal medicine, Monthey, Switzerland, 8Centre Hospitalier Universitaire Vaudois CHUV and University of Lausanne, Division of Visceral Surgery, Lausanne, Switzerland


Data of large cohort studies on the fate of perianal fistulizing Crohn’s disease (CD) is scarce. We aimed to evaluate the prevalence and natural history of perianal fistulas in adults with Crohn’s disease (CD).


Data from the Swiss IBD cohort study were analysed. The Swiss IBD Cohort study includes since 2006 IBD patients, follow-up questionnaires are completed once a year. Patients were recruited from university centres (80%), regional hospitals (19%), and private practices (1%).


Among 2163 CD patients, 495 (22.9%) ever had perianal fistulas whereas 1668 (77.1%) did not. Patients with perianal fistulas were characterised by the following features when compared with patients without perianal fistulas: younger age at diagnosis (23.4 vs. 25.3 years, p = 0.001), longer disease duration at enrolment (9.6 vs. 4.9 years, p < 0.001), longer disease duration at latest follow-up (17.4 vs. 11.2 years, p < 0.001), less frequenty isolated ileal disease at diagnosis (15.8% vs. 28.6%, p < 0.001), more frequently rectal disease at enrolment (32.5% vs. 14.8%, p < 0.001) and latest follow-up (24.2% vs. 11.7%, p < 0.001), more frequently acne inversa (1.4% vs. 0.1%, p < 0.001), and more frequently intestinal resection (49.5% vs. 35.3%, p < 0.001). The prevalence of extraintestinal manifestations was not different (59.0% vs. 54.4%, p = 0.073). Compared with patients without perianal fistulas, patients with perianal fistulas were more frequently treated with topical 5-ASA (14.8% vs. 8.0%, p < 0.001), systemic steroids (78.2% vs. 70.1%, p < 0.001), azathioprine (82.6% vs. 77%, p = 0.008), methotrexate (28.3% vs. 22.2%, p = 0.005), infliximab (71.9% vs. 50.8%, p < 0.001), adalimumab (36% vs. 27.9%, p < 0.001), certolizumab pegol (18.6% vs. 11.5%, p < 0.001), and antibiotics (69.1% vs. 41.2%, p < 0.001). Regarding fistula anatomy, 321 patients (64.8%) had a low perianal fistula, 82 (16.6%) a high perianal fistula, and 227 (45.9%) a perineal fistula. The following fistula therapies were ever applied: perianal abscess drainage (45.7%), fistulectomy/fistulotomy (39.6%), seton drainage (28.7%), mucosal sliding flap (2%), fistula plug (1.4%), and fibrin glue instillation (1%).


In our national cohort roughly one-quarter of CD patients was diagnosed with perianal fistulizing disease. Compared with patients without perianal fistulas, patients with perianal fistulizing disease were characterised by several stigmata of complicated disease course such as a higher frequency of intestinal resections and higher prevalence of treatment with biologic agents.