Su1335 A Novel Description of Longitudinal Phenotype in Patients With Crohn's Disease

Abstract

BACKGROUND: The Montreal classification for patients with Crohn's disease describes disease phenotype in a hierarchy: B1 (Inflammatory), B2 (Stricturing), B3 (Internal Penetrating). It does not make allowance for description of resolution, or of repeated development, of internal penetrating or stricturing complications (IPSC). It therefore always observes increasing severity of disease phenotype over time, and does not accurately represent the burden of IPSC later in the disease course. AIM: To describe a novel classification of longitudinal disease phenotype in Crohn's disease, which allows description of both resolution and repeated development of IPSC. METHODS: Patients diagnosed at a tertiary referral centre (Brisbane, Australia) with Crohn's disease between 1st Jan 1994 and 1st March 2008, with more than five years of clinical follow-up, had all objective clinical data recorded in a longitudinal database. Temporal evidence of presence of IPSC was obtained from the following: computed tomographic enterography (CTE), magnetic resonance enterography (MRE), ileocolonoscopy, gastroscopy, findings at abdominal surgery and examination of macroscopic surgical specimens. Disease phenotype at each time point was classified as the presence or absence of IPSC over the previous three years of disease course. Longitudinal disease phenotype was compared to progressive Montreal phenotype. Subgroup analysis was performed for patients with B1, B2 or B3 Montreal phenotype within one year of diagnosis. RESULTS: 316 patients with a median follow-up of 10.0 years (interquartile range (IQR) 6.81 13.67) were analyzed. Mean age at diagnosis was 27.4 years and 55% were female. Montreal location classification at diagnosis was L1 (131 patients), L2 (58) and L3 (117). Progressive Montreal phenotype was comparable to published cohorts.1 In comparison longitudinal phenotype classification demonstrated a predominance of stricturing complications. Stricturing complications predominated regardless of Montreal phenotype within the first year (graphs not shown). The steep slope in all lines at 3 years represents patients with an isolated IPSC at presentation regressing to a less severe classification. CONCLUSION: B2 (Stricturing) complications make up the bulk of recurring or non-resolving IPSC in patients with Crohn's disease, regardless of Montreal phenotype within one year of diagnosis. This is not evident when disease classification is observed using the Montreal classification system alone. 1: Tarrant KM, Barclay ML, Frampton CMA, Gearry RB. Perianal disease predicts changes in Crohn's disease phenotype-results of a population-based study of inflammatory bowel disease phenotype. Am J Gastroenterol. 2008 Dec;103(12):3082-93.