Venous thromboembolism and subsequent hospitalisation due to acute arterial cardiovascular events: a 20-year cohort study

Background Venous thromboembolism has been associated with atherosclerosis and with the risk of arterial cardiovascular events such as myocardial infarction and stroke in some studies, but overall the available data are conflicting. Methods We performed a 20 year population-based cohort study using nationwide Danish medical databases. After excluding those with known cardiovascular disease, we examined the risk of hospitalization due to myocardial infarction and stroke among 25 199 patients with deep venous thrombosis, 16 925 patients with pulmonary embolism and 163 566 population controls. Findings Patients with both deep venous thrombosis and pulmonary embolism had a substantially increased risk of myocardial infarction and stroke during the first year after the thrombotic event. For patients with deep venous thrombosis, the relative risks varied from 1•60 for myocardial infarction (95% CI 1•35 – 1•91) to 2•19 (95% CI 1•85 – 2•60) for stroke. For patients with pulmonary embolism, the relative risks were 2•60 (95% CI 2•14 –3•14) for myocardial infarction and 2•93 (95% CI 2•34 – 3•66) for stroke. The relative risks were also elevated, though less markedly, during the subsequent 20 years of follow-up, with 20 to 40% increases in risk for arterial cardiovascular events. Relative risks were similar for those with provoked and unprovoked deep venous thrombosis and pulmonary embolism. Interpretation Patients with venous thromboembolism have a substantially increased long-term risk of subsequent arterial cardiovascular events.