Risk of Ischemic Stroke in Patients with Crohn's Disease: A Population-based Nested Case-control Study

Background: Observational studies have linked Crohn's disease (CD) to an increased risk of venous thromboembolic complications. Case reports of ischemic stroke in CD patients have raised the question of a similar association, but data from observational studies are lacking. Methods: Using data from the UK General Practice Research Database we conducted a nested case-control analysis within a population-based cohort of 8054 patients with and 161,078 patients without CD. A total of 1748 cases of ischemic stroke were identified to whom 17,348 controls were matched on age, sex, and year of cohort entry. Adjusted odds ratios (ORs) of ischemic stroke associated with CD were calculated by conditional logistic regression. Stratified analyses were performed for age and sex. Results: While CD was not associated with an overall increased risk of ischemic stroke (OR 1.10, 95% confidence interval [CI] 0.85-1.43), stratified analyses revealed an increase in risk in younger patients (<50 years: OR 2.93; 95% CI 1.44-5.98) but not in elderly patients (>= 50 years: OR 0.99; 95% CI 0.75-1.30; P for interaction <0.01). The interaction with age remained statistically significant even after changing the cutoff value for the younger and older age group to 45, 55, or 60 years in a sensitivity analysis. There was no interaction with sex (P = 0.79). Conclusions: The study indicates that younger patients with CD may be under an increased risk of ischemic stroke.