P239 Elderly-onset inflammatory bowel disease is associated with higher risks of infections, cancers and hospitalisation: Results from a territory-wide Hong Kong IBD registry

Abstract Background Incidence of elderly-onset inflammatory bowel disease (IBD), defined as age ≥ 60 at diagnosis, is increasing rapidly worldwide. We aimed to compare the clinical characteristics and natural history of elderly onset IBD patients to non-elderly onset IBD patients. Methods Patients with a confirmed diagnosis of IBD from 1981 to 2016 were identified from a territory-wide Hong Kong IBD registry involving 13 hospitals. Demographics, comorbidities, clinical features and outcomes of elderly-onset IBD patients were compared with non-elderly onset IBD patients. Results Total 2413 patients were identified, of whom 270 (11.2%) had elderly-onset IBD during 21805 person-years follow-up. Median follow-up duration was 111 months (Interquartile range [IQR]: 68–165 months). The ratio of ulcerative colitis (UC): Crohn’s disease (CD) was higher in elderly-onset IBD than non-elderly onset IBD patients. (3.82:1 vs. 1.39:1; p < 0.001). Elderly-onset Crohn’s disease (CD) had less perianal involvement (5.4% vs. 25.4%; p < .001) but more stricturing phenotype (32.1% vs. 20.5%; p = 0.04) than non-elderly onset. There was no difference in the rate of cumulative use of biologics (p = 0.49), but significantly lower use of immunosuppressants in elderly-onset IBD patients (p = 0.001). Cumulative risk of IBD-related surgeries was similar (p = 0.89). Elderly-onset IBD was associated with higher risks of cytomegalovirus colitis (Odds ratio [OR]: 3.07; 95% Confidence Interval (CI) 1.92–4.89; p < 0.001); herpes zoster infections (OR: 2.42; 95% CI: 1.22–4.80; p = 0.12) and all cancer development (Hazard ratio: 2.97; 95% CI: 1.84–4.79; p < 0.001). Elderly-onset IBD was also associated with increased number of overall hospitalisation (OR: 1.14; 95% CI 1.09–1.20; p < 0.001), increased number of infections-related hospitalisation (OR: 1.87; 95% CI 1.47–2.38; p < 0.001) and longer hospitalisation (OR: 1.004; 95% CI: 1.001- 1.007; p = 0.007) compared with non-elderly onset IBD. Conclusion Elderly-onset IBD has less perianal CD. However, they have significantly more comorbidities and are associated with increased risk of infections, cancer development and increased and prolonged hospitalisations. Specific therapeutic strategies are needed in this special group of patients.