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.