Influence of age at diagnosis on the clinical characteristics of Crohn's disease in Korea: Results from the CONNECT study

Background and Aim: The present study evaluated the clinical characteristics of Korean patients with Crohn's disease (CD) according to their age at diagnosis in a nationwide multicenter cohort study. Methods: A total of 1224 patients diagnosed with CD between 1982 and 2008 in 32 hospitals were included, and age at diagnosis was categorized as 16 (G1), 17-40 (G2), 41-59 (G3) and 60 (G4) years old. The baseline characteristics, medication, and intestinal resection were compared according to the age at diagnosis. Results: The number of patients in each age group was 155 (G1; 12.7%), 919 (G2; 75.1%), 120 (G3; 9.8%), and 30 (G4; 2.5%). The frequencies of ileocolonic disease in the late adult onset and elderly onset groups were lower than those in the other groups (P<0.001). The cumulative probabilities of thiopurine and anti-tumor necrosis factor use in late adult onset and elderly onset groups were significantly reduced compared with those of the other groups (P<0.01). However, the risk of the first intestinal resection was not different among the age groups. The ileal location (hazard ratio [HR]: 1.59; 95% confidence interval [CI]: 1.11-2.27), complicated behavior (HR: 3.35; 95% CI: 2.63-4.27), and early thiopurine use (HR: 0.27; 95% CI: 0.17-0.43) were associated with the first intestinal resection, whereas the age at diagnosis was not a risk factor. Conclusions: Elderly onset CD may be related to favorable outcomes in Korea. Thus, the heterogeneity of this disease should be considered when developing a tailored strategy for the treatment of CD.