Epidemiology and Natural History of Elderly-onset Inflammatory Bowel Disease: Results From a Territory-wide Hong Kong IBD Registry

Background: Elderly-onset inflammatory bowel disease (IBD], defined as age >= 60 at diagnosis, is increasing worldwide. We aimed to compare clinical characteristics and natural history of elderlyonset IBD patients with those of adult-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 those of adultonset IBD patients. Results: A total of 2413 patients were identified, of whom 270 111.2%] had elderly-onset IBD. Median follow-up duration was 111 months (interquartile range [IQR]: 68-165 months). Ratio of ulcerative colitis [UC]: Crohn's disease [CD] was higher in elderly-onset IBD than in adult-onset IBD patients [3.82:1 vs 1.39:1; p <0.001]. Elderly-onset CD had less perianal involvement [5.4% vs 25.4%; p <0.001 than adult-onset CD. Elderly-onset IBD patients had significantly lower cumulative use of immunomodulators [p= 0.001] and biologics (p= 0.04]. 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 [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 <0.0011.They also had increased number of overall hospitalisations [OR: 1.14; 95% CI 1.09-1.20; p <0.001], infections-related hospitalisation [OR: 1.87; 95% CI 1.47-2.38; p<0.001], and IBD-related hospitalisation [OR: 1.09; 95% CI 1.04- 1.15; p= 0.001] compared with adult-onset IBD patients. Conclusions: Elderly-onset IBD was associated with increased risk of infections and cancer development, and increased infection- and IBD-related hospitalisations. Specific therapeutic strategies to target this special population are needed.

Automated summary

Elderly-onset IBD patients exhibit different clinical characteristics and disease course compared to adult-onset IBD patients, with a higher risk of infections and cancer development. These patients also have increased hospitalizations related to infections and IBD, highlighting the need for specific therapeutic strategies for this special population.