Increased risk of arterial thromboembolism after a prior episode of venous thromboembolism: results from the Prevention of REnal and Vascular ENd stage Disease (PREVEND) Study

Large population-based studies are needed to establish the magnitude and duration of the recently suggested association between arterial and venous thromboembolism. In 199798, all inhabitants of Groningen, the Netherlands, aged 2875 years (n = 85 421), were invited to participate in a study that followed and monitored responding subjects (n = 40 856) for venous and arterial thromboembolism until 2009. Thromboembolism was verified with national registries of hospital discharge diagnoses and death certificates, anticoagulation clinic and medical records. During a median follow-up of 10.7 years, 549 participants developed venous thromboembolism and 3283 developed arterial thromboembolism. Annual incidence of arterial thromboembolism after venous thromboembolism was 2.03% [95% confidence interval (CI), 1.482.71], compared to 0.87% (95% CI, 0.840.90) in subjects without venous thromboembolism. The hazard ratio (HR) of arterial thromboembolism after venous thromboembolism was 1.40 (95% CI, 1.041.88) after adjustment for age, sex and cardiovascular risk factors. This risk was highest during the first year after venous thromboembolism [annual incidence, 3.00% (95% CI, 1.645.04); adjusted HR, 2.01 (95% CI, 1.193.40)] and after an unprovoked event [annual incidence, 2.53% (95% CI, 1.683.66); adjusted HR, 1.62 (95% CI, 1.112.34)]. This study showed that subjects with venous thromboembolism are at increased risk for arterial thromboembolism, particularly in the first year after venous thromboembolism and after an unprovoked event.