Venous Thromboembolism Risk in Asian Patients with Inflammatory Bowel Disease: A Population-Based Nationwide Inception Cohort Study

Background/Aims: Inflammatory bowel disease (IBD) is associated with the occurrence of venous thromboembolism (VTE). However, to date, there have been few studies on the risk of VTE in Asian IBD patients. We aimed to estimate the incidence of VTE in Asian IBD patients and to determine if IBD is related to increased VTE risk. Methods: We performed a population-based cohort study between 2004 and 2015 using Korean National Health Insurance data. IBD and VTE were defined by ICD-10 codes. Incidence rates of VTE were calculated among patients with IBD and among age- and sex-matched controls. Hazard ratios were estimated using Cox regression with adjustment for multiple variables. We performed additional analyses stratifying by age, sex, Charlson comorbidity index (CCI) score, and disease type. Results: Among the 45,037 patients with IBD (IBD cohort) and 133,019 matched controls (non- IBD cohort) included in our analysis, 411 IBD patients and 641 controls developed VTE. The IBD cohort had a higher incidence rate ratio and risk of VTE than the non-IBD cohort (incidence rate ratio: 1.92 and hazard ratio: 1.93). Older age, female sex, higher CCI scores, cardiovascular disease, chronic kidney disease, use of steroids, and hospitalization were significant risk factors for VTE in patients with IBD. Conclusions: The IBD patients in this study were approximately two times more likely to develop VTE than the non-IBD individuals. Our findings support the need for thromboprophylaxis in Asian IBD patients with various factors that further increase the risk of VTE.