P1107 Clinical characteristics and prognosis of very young adult-onset Crohn's disease: Results from the Prospective CONNECT Study

Abstract

Abstract Background Although the A2 group according to the Montreal classification accounts for the largest proportion among patients with Crohn’s disease (CD),1 there has been a lack of studies comparing the clinical characteristics and prognosis according to the age at diagnosis within the A2 group. Methods We utilised data from the prospective CONNECT study—a nationwide, multicentre cohort study of CD patients in Korea.2 Of 1,175 participants, a total of 945 patients (80.4%) were categorised as Montreal classification of age A2 (≥17 and <40 years at diagnosis). They were further divided into two groups based on the age at diagnosis: very young adult-onset group (≥17 and <20 years, n=275) and young adult-onset group (≥20 and <40 years, n=670). Results Isolated ileal diseases were more common in the young adult-onset group (21.5% vs. 30.7%), whilst the frequency of stricturing (B2) or penetrating (B3) behaviours was tended to be lower in the very young adult-onset group than in the young adult-onset group (16.7% vs. 29.7%) (Table 1). Twenty-five patients (9.1%) in the very young adult-onset group underwent intestinal resection compared to 91 patients (13.6%) in the young adult-onset group (p=0.072). The very young adult-onset group had a longer intestinal resection-free survival than the young adult-onset group (p=0.04) (Figure 1a). More patients in the very young adult-onset group received systemic corticosteroids compared with those in the young adult-onset group (62.2% vs. 48.8%, p<0.001) and the corticosteroid-free survival was shorter in the very young adult-onset group compared with the young adult-onset group (p<0.01) (Figure 1b). Complicated behaviors (B2, adjusted hazard ratio [aHR] 4.03, 95% confidence interval [CI] 2.42–6.70, p<0.001; B3, aHR 6.39, 95% CI 4.21–9.72, p<0.001) was independently associated with the risk of intestinal resection. Conclusion The very young adult-onset group exhibited distinct disease behaviour at diagnosis and different clinical outcomes compared with the young adult-onset group. Within the A2 group (≥17 and <40 years at diagnosis), the risk of intestinal resection appears to be driven by the intestinal complications.