Long‐term trend of cumulative incidence of venous thromboembolism in Korean pediatric inflammatory bowel disease

Background Research on venous thromboembolism (VTE) in pediatric inflammatory bowel disease (PIBD) is rare in Asia. This study aimed to investigate the epidemiological characteristics of VTE within the Korean PIBD population. Methods A cohort study was conducted on pediatric patients (<17 years) using South Korea's health claims data from 2005 to 2015. IBD and VTE were identified using ICD‐10 codes. We analyzed incidence rate, cumulative incidence, and risk factors, including very early‐onset (VEO, <6 years) IBD. Results Among 2456 newly diagnosed PIBD patients (2005–2015), 15 (0.6%) developed VTE. The overall VTE incidence was 11.08 per 10,000 patient‐years, with rates of 76.72 for VEO‐IBD and 9.79 for late‐onset (LO, 6–16 years) PIBD. Cumulative VTE rates at 0, 1, 5, and 10 years were 0.04%, 0.08%, 0.56%, and 1.26%, respectively. Age at onset increased VTE risk, while gender and disease type did not show significant differences. Conclusions The incidence of VTE in PIBD steadily increased over the 10‐year period, with a higher occurrence in those with VEO‐IBD. This study emphasizes the importance of continuous follow‐up for VTE from the early stages of the disease in pediatric IBD patients, particularly focusing on younger age groups.