S1179 Clinical Characteristics of Non-Stricturing Non-Penetrating Crohn's Disease Based on Age at Diagnosis

Abstract

Background: Older age at diagnosis has been independently associated with a lower risk of complications in Crohn's disease (CD). Previous reports have been based on the Vienna classification. Exclusion of perianal disease as penetrating disease in theMontreal classification may lead to important differences that explain improved prognosis in the older age groups. Aim: To compare disease characteristics between patients with non-stricturing non-penetrating Crohn's disease (CD) diagnosed before and after 40 years of age. Methods: Historical cohort analysis of 202 CD patients with non-stricturing non-penetrating CD followed from diagnosis to development of complications (stenotic or penetrating) or last clinical followup. Disease location, perianal disease, family and smoking history, immunomodulator use were compared among those diagnosed before (younger) and after (older) 40 years of age. Overall influences on the development of complications were determined. Results: Of the 202 patients, 12 % of patients developed complications. Duration of follow up was longer in those diagnosed before age 40 (13.9 vs. 10.4 years; p=0.02). Development of complications was far more common in the younger age group compared to the older (19.3 vs. 3.2%; p<0.0001) as was perianal disease (33 vs. 9.8%; p<0.001). Isolated colonic disease was more common in the older group (44 vs. 28%; p=0.02). Immunomodulator use was greater in the younger group (61 vs. 38%, p=0.001). Biologic use was generally episodic and more frequent in the younger group (20 vs. 7%;p=0.01). Surgery rates were similar. Smoking at diagnosis was also more common in the younger group (28 vs. 14%; p=0.02) whereas family history was similar between the two groups. In a multivariate Cox proportional hazards model only older age at diagnosis was associated with a lower risk of complications (hazard ratio 0.15) after adjustment for calendar time. Conclusion: Clinical characteristics differ among patients diagnosed with non-stricturing non-penetrating CD before and after 40 years of age and suggestmilder disease in the older age group. Thismay have important implications for prognosis . Despite these apparent differences, only age at diagnosis predicted risk of complications. Rates of progression to complications were low with the adoption of the Montreal classification.