P196 Colon-involving versus non-colon-involving Crohn’s disease classification: is the Montreal classification outdated?

Capela, T.(1,2,3);Macedo Silva, V.(1,2,3);Freitas, M.(1,2,3);Cúrdia Gonçalves, T.(1,2,3);Dias de Castro, F.(1,2,3);Moreira, M.J.(1,2,3);Cotter, J.(1,2,3);

(1)Hospital da Senhora da Oliveira, Gastroenterology Department, Guimarães, Portugal;(2)School of Medicine- University of Minho, Life and Health Sciences Research Institute ICVS, Braga, Portugal;(3)ICVS/3B's, PT Government Associate Laboratory, Braga / Guimarães, Portugal


An appropriate disease classification is essential for the management of Crohn’s disease (CD) patients. Recently, a new classification of colon-involving versus non-colon-involving disease extension was considered to be more predictive of adverse outcomes than the Montreal classification (MRC). We aimed to investigate the association of a colon-based classification with clinically relevant outcomes in patients with CD compared with the MRC.


Retrospective cohort-study which consecutively included adult CD patients with at least 1 year of follow-up. Patients were categorized into colon-involving and non-colon-involving disease and according to the MRC. Patients’ demographic, clinical, biochemical, and imaging data were recorded and compared between the two classifications. The primary outcome was the need for treatment with steroids or biologics, hospitalization and major abdominal surgery.


Of 327 patients, 52.3% were female with a mean age of 43.3±13.1 years. The most common disease location according to MRC was L1 (48.9%), followed by L3 (41.3%) and L2 (9.8%). Overall, 51.1% of patients had colon-involving disease. Although patients with colon-involvement at diagnosis had higher frequency of perianal lesions (27.5% vs 16.9%, P<0.05) and serum inflammatory biomarkers (lower hemoglobin, and higher leucocyte and platelet counts, c-reactive protein and erythrocyte sedimentation rate), this classification was not predictive of relevant outcomes. Considering the two types of colon-involving disease (L2, L3), patients with L2 disease had higher extraintestinal manifestations (43.8% vs 20.7%, respectively, P<0.05), higher B1 disease behavior (87.5% vs 58.5%, respectively, P<0.05) and lower B2 disease behavior (6.25% vs 22.2%, respectively, P<0.05). Disease location according to MRC was predictive of the need for treatment with biologics, hospitalization and major abdominal surgery in univariate analysis, but not in multivariate analysis.


Although simpler, defining Crohn’s disease extension by colon-involving versus non-colon-involving is not more predictive of adverse outcomes than the Montreal classification. Therefore, the use of Montreal Classification should still be considered essential in the adequate management of IBD patients.