Long-term Risk of Stroke in Patients With Inflammatory Bowel Disease: A Population-Based, Sibling-Controlled Cohort Study, 1969-2019.

Abstract

Patients with inflammatory bowel disease (IBD) are at an increased risk of thromboembolic events, but evidence on the long-term risk of stroke remains scarce. We aimed to explore whether patients with a biopsy-confirmed IBD had an increased long-term risk of stroke. This cohort included all patients with biopsy-confirmed IBD in Sweden between 1969 and 2019 and up to 5 matched reference individuals per patient who were randomly selected from the general population and IBD-free full siblings. The primary outcome was incident overall stroke; secondary outcomes were ischemic and hemorrhagic strokes. Stroke was identified from the Swedish National Patient Register by using both primary and secondary diagnoses. Adjusted hazard ratios (aHRs) for stroke were estimated by flexible parametric survival models. A total of 85,006 patients with IBD (including Crohn disease [CD, n = 25,257], ulcerative colitis [UC, n = 47,354], and IBD-unclassified [IBD-U, n = 12,395]), 406,987 matched reference individuals, and 101,082 IBD-free full siblings were included in the analysis. We observed 3,720 incident strokes in patients with IBD (incidence rate [IR] 32.6 per 10,000 person-years) and 15,599 in reference individuals (IR 27.7; aHR 1.13, 95% CI 1.08-1.17). The elevated aHR remained increased even 25 years after diagnosis, corresponding to 1 additional stroke case per 93 patients with IBD until then. The excess aHR was mainly driven by ischemic stroke (aHR 1.14; 1.09-1.18) rather than hemorrhagic stroke (aHR 1.06; 0.97-1.15). The risk of ischemic stroke was significantly increased across IBD subtypes (CD [IR 23.3 vs 19.2; aHR 1.19; 1.10-1.29], UC [IR 25.7 vs 22.6; aHR 1.09; 1.04-1.16], and IBD-U [IR 30.5 vs 22.8; aHR 1.22; 1.08-1.37]). Similar results were found when patients with IBD were compared with their siblings. Patients with IBD were at an increased risk of stroke, especially of ischemic events, irrespective of the IBD subtype. The excess risk persisted even 25 years after diagnosis. These findings highlight the need for clinical vigilance about the long-term excess risk of cerebrovascular events in patients with IBD.