The Risk of Venous Thromboembolism in Children With Inflammatory Bowel Disease.

Background: Recent studies of children with inflammatory bowel disease (IBD) demonstrate an increased venous thromboembolism (VTE) risk. However, estimates of risk are variable and case numbers are limited. The aim of this study was to provide national estimates of the risk of VTE in children with IBD.

Methods: Hospital Episode Statistics was used to identify patients diagnosed with either IBD or VTE before reaching 18 years of age between 2001 and 2019. Populations and subgroups are described, and the risks of developing VTE in the general and IBD populations were calculated.

Results: Children with VTE following a diagnosis of IBD or in the previous 6 months (n = 85) and with VTE without IBD (n = 4160) were studied. The absolute risk in children with IBD was 9.42 (95% confidence interval [CI], 7.4-11.4) per 10 000 patient-years, compared with 0.18 (95% CI, 18-0.19) in children without IBD. Between 6 months prior to and 1 year following IBD diagnosis was the highest absolute risk period for VTE (18.0; 95% CI, 13.7-22.4). The relative risk of VTE in children with IBD vs children without IBD was greatest in younger patient groups: the relative risk for the age band 0 to 8 years was 96.5 (95% CI, 51.8-179.9) and for 9 to 11 years was 153.1 (95% CI, 81.2-288.8) vs 14.3 (95% CI, 10.3-20.0) for 15 to 17 years. Cerebral venous sinus thrombosis represented 17.6% of pediatric VTE events in IBD patients compared with 4.2% in children without IBD (P = .001).

Conclusions: This study confirms the increased risk of VTE in children with IBD compared with children without IBD. The time of greatest VTE risk was around diagnosis. Cerebral venous sinus thrombosis was significantly more common in children with IBD than other children.