Incidence and cumulative recurrence rates of venous thromboembolism in the Taiwanese population

Summary. Background: Little information is available on the epidemiology of venous thromboembolism (VTE) in Asian populations. Objectives: To investigate VTE incidence, VTE cumulative recurrence rates and risk factors for VTE recurrence among the adult Taiwanese population. Methods: This population‐based cohort study used the Taiwanese National Health Insurance claims databases to identify 5347 adult patients (2463 men, 46.1%) with VTE diagnosed in 2001 and 2002. We calculated the crude incidence of VTE and its recurrence. We also conducted a nested case–control study (n = 3576) among this population to estimate the association between VTE recurrence and exposure to potential VTE risk factors by conditional logistic regression. Results: The crude incidence of VTE was 15.9 per 100 000 person‐years, and its recurrence rate was 5.1% per person‐year. During 11 566 person‐years of follow‐up, the cumulative rates of VTE recurrence at 6, 12, 24, 36 and 47 months were 6.7%, 9.4%, 12.4%, 13.9%, and 14.4%, respectively. By conditional logistic regression, histories of VTE [adjusted odds ratio (OR) 1.71, 95% confidence interval (CI) 1.32–2.16] or malignant neoplasm (adjusted OR 1.64, 95% CI 1.26–1.99), major extremity trauma (adjusted OR 2.76, 95% CI 1.82–4.52), serious neurologic diseases (adjusted OR 1.43, 95% CI 1.12–1.84) or undergoing major surgery (adjusted OR 4.57, 95% CI 1.72–12.50) were associated with higher risks of VTE recurrence. Conclusions: The incidence of VTE is lower in the Taiwanese population than in Caucasians. Most VTE recurrences occur within 12 months, but they continue to occur beyond 1 year. The VTE recurrences are associated with malignancy, history of VTE, and major surgery after a previous VTE.