OP19 Classifying perianal fistulising Crohn’s Disease: An expert-consensus to guide decision-making in daily practice and clinical trials

Geldof, J.(1);Iqbal, N.(2);LeBlanc, J.F.(3);Sawyer, R.(4);Buskens, C.(5);Bemelman, W.(5);Gecse, K.(6);Lundby, L.(7);Lightner, A.L.(8);Danese, S.(9);Spinelli, A.(10);Carvello, M.(10);Faiz, O.(11);Warusavitarne, J.(11);Lung, P.(12);De Looze, D.(13);D’Hoore, A.(14);Vermeire, S.(15);Hart, A.(3);Tozer, P.(16);

(1)UZ Gent, Gastroenterology and Hepatology, Gent, Belgium;(2)St Mark’s Hospital and Academic Institute, Robin Phillips Fistula Research Unit-, London, United Kingdom;(3)St Mark’s Hospital and Academic Institute, IBD unit, London, United Kingdom;(4)St Mark’s Hospital and Academic Institute, patient representative, London, United Kingdom;(5)Amsterdam University Medical Center- Gastroenterology Endocrinology Metabolism Research Institute, Department of Surgery, Amsterdam, The Netherlands;(6)Amsterdam University Medical Center, Department of Gastroenterology and Hepatology, Amsterdam, The Netherlands;(7)Aarhus University Hospital, Department of Surgery- Pelvic Floor Unit, Aarhus, Denmark;(8)Cleveland Clinic, Center for Regenerative Medicine and Surgery Colorectal Surgery Digestive Disease Institute Inflammation and Immunity Lerner Research Institute Center for Immunotherapy, Cleveland, United States;(9)Vita-Salute San Raffaele University- IRCCS Hospital San Raffaele, Milan, Italy;(10)Humanitas University- IRCCS Humanitas Research Hospital, Department of Biomedical Sciences, Milan, Italy;(11)St Mark’s Hospital and Academic Institute, Department of Colorectal Surgery, London, United Kingdom;(12)St Mark’s Hospital and Academic Institute, Radiology department, London, United Kingdom;(13)University Hospital Ghent, Department of Gastroenterology and Hepatology, Ghent, Belgium;(14)University Hospitals Leuven, Department of Abdominal Surgery, Leuven, Belgium;(15)University Hospitals Leuven, Department of Gastroenterology and Hepatology, Leuven, Belgium;(16)St Mark’s Hospital and Academic Institute- and Imperial College, Robin Phillips Fistula Research Unit- Department of Colorectal Surgery-, London, United Kingdom;


Perianal fistulising Crohn’s disease (CD) is an aggressive disease phenotype that can have a significant impact on patients’ quality of life. Current biological understanding of perianal fistulising CD remains inadequate and previous classification systems have not provided clear guidance on therapy in clinical practice nor on defining patient cohorts within clinical trials. To counter this unmet need, we propose a new classification system for perianal fistulising CD. 


The proposed classification system was developed through a modified nominal group technique expert consensus process involving open discussion and formal voting on previously defined statements. Consensus agreement was defined a priori as 80% voting “strongly agree” or “agree with minor reservation”. Participants included gastroenterologists, radiologists, surgeons active in a tertiary IBD centre and a patient representative.


The classification identifies four groups of patients with perianal fistulising CD. Key elements include stratification according to disease severity as well as disease outcome; synchronisation of patient and clinician goals in decision making, with a proactive, combined medical and surgical approach, on a ‘treat to patient goal' basis; and identification of indications for curative fistula treatment, diverting ostomy and proctectomy. The new classification retains an element of flexibility, in which patients can cycle through different classes over time. Furthermore, with each specific class comes a paired treatment strategy suggestion and description of clinical trial suitability.

Figure 1. Classification of perianal fistulising Crohn’s disease (CD)


The proposed classification system is the first of its kind and is an important step towards tailored standardisation of clinical practice and research in patients with perianal fistulising CD.