Epidemiology of Elderly-Onset IBD: A Nationwide Population-based Cohort Study.

Background and aims: We examined the incidence and natural history of patients with very elderly-onset (herein, referred to as very late-onset) inflammatory bowel diseases (IBD) (age ≥70y at diagnosis), compared with patients diagnosed between ages 60-69y in Denmark.

Methods: In the Danish National Patient Register, between 1980-2018, we identified all individuals ≥60y with newly diagnosed Crohn's disease (CD) and ulcerative colitis (UC) and examined trends in incidence, cumulative risk of hospitalization, treatment patterns, IBD-related surgery, serious infection, cancer and cardiovascular and venous thromboembolic risks among very late-onset (70-79y or 80+ years) vs. late-onset (60-69y) IBD, using non-parametric competing risk analysis treating death as competing risk.

Results: We identified 3,459 patients with onset of CD at age ≥60y (47% ≥70y) and 10,774 patients with onset of UC aged ≥60y (51% ≥70y). Over the last three decades, incidence changes for very late-onset and late-onset IBD have followed the same patterns. Also, both for CD and UC, cumulative incidence of IBD-related hospitalization and corticosteroid use was comparable in very late-onset vs. late-onset patients. However, the burden of disease-modifying therapy, either immunomodulator or TNF antagonist use, and major IBD-related surgery was significantly lower in patients with very late-onset than in late-onset IBD. On the other hand, 5-year risk of serious infections and cardiovascular events was higher in patients with very late-onset IBD.

Conclusion: This nationwide cohort study shows that patients diagnosed with very late-onset (≥70y) IBD have a higher relative burden of disease- and aging-related complications, with limited use of steroid-sparing strategies and surgery, compared with late-onset IBD.