Blood pressure and risk of venous thromboembolism: a cohort analysis of 5.5 million UK adults and Mendelian randomization studies.

In a large-scale population cohort, with over 100,000 first episodes of VTE and a median follow-up of about 10 years, we found a 7% higher risk of VTE for each 20 mmHg lower systolic blood pressure. The association was comparable when we examined pulmonary embolism and deep venous thrombosis separately, and persisted after taking into account age and other factors, including anticoagulant treatment during follow-up. These results were confirmed using two independent Mendelian randomization studies. Although the beneficial effects of blood pressure-lowering are likely to outweigh any harms in most patient groups, clinicians should be aware of the potential risk of VTE from antihypertensive therapy, in particular in people who have predisposing factors for VTE.