Background: The incidence of Crohn’s disease (CD) and ulcerative colitis (UC) in the elderly population is reported to be increasing. Comorbid diseases, which are more prevalent with advanced age, may impact the natural history of inflammatory bowel disease (IBD) and treatments. We sought to characterize the population-based burden and outcomes of elderlyonset CD and UC in comparison to IBD of younger onset.
Methods: We identified incident cases of IBD in Ontario, Canada between 1999 and 2008 from health administrative databases at the Institute for Clinical Evaluative Sciences using algorithms that were validated specifically in Ontario. The primary outcomes were hospitalizations and first IBO-related surgery. We compared groups defined by age at diagnosis: young adult (18-44y); middle-adult (45-64y); and elderly (~65y) in univariate and regression analysis. Comorbidity was assessed using the validated Johns Hopkins Adjusted Clinical Group (ACG) case-mix system.
Results: There were 8,985 incident cases of CD and 12,233 incident cases of UC during the study period. Of these, 725 new cases of CD and 1,749 new cases of UC occurred in the elderly. There was a slightly greater female predominance among the elderly group. More than a quarter of elderly IBD patients (29% of CD; 26% of UC) were in the top quartile for ACG comorbidity score, which was about twice as frequent as the middle-adult group. The incidence of IBDrelated hospitalization adjusted for sex, ACG comorbidity, and geographic region was lower for elderly IBD subjects when compared with young adults in both CD (incidence rate ratio IIRR], 0.76; 95% CJ: 0.69 – 0.83) and !JC (IRR, 0.88; 95% CI: 0.82 – 0.96). The KaplanMeier survival curves for bowel surgery for UC and CD stratified by age at diagnosis are shown in Figure 1. The cumulative risk of CD-related bowel resection at 2, 5, and 10 years were 18%, 24%, and 31 %, respectively for elderly CD patients which were similar to the 15%, 23%, and 30% cumulative risks observed in young adults with CD. In contrast, the cumulative risk of colectomy among elderly UC patients at 2, 5, and 10 years.were 18%, 24%, and 31%, respectively for elderly CD patients which were similar to the 15%, 23%, and 30% cumulative risks observed in young adults with CD. In contrast, the cumulative risk of colectomy among elderly UC patients at 2, 5, and 10 years (9%, 14%, and 18%, respectively) was higher than that of middle-age adults (8%, 11%, and 15%, respectively) and young adults (7%, 10%, and 13%, respectively). The adjusted hazard ratio for colectomy among elderly UC patients compared with their young adult counterparts was 1.36 (95% CI: 1.18 – 1.57).
Conclusion: In this population-based study, UC patients who were diagnosed after age 65 years incurred increased risk of colectomy compared to those diagnosed as young, or middle-age adults. It is unclear whether this was due to more a more aggressive disease course or a lower threshold for colectomy due to the potential adverse effects of immunosuppressive medical therapy.
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