Higher blood pressure is associated with a lower risk of venous thromboembolism (VTE), according to a study of more than 100,000 people diagnosed with VTE in the United Kingdom. The study was conducted by researchers at the University of Oxford’s George Institute for Global Health, Oxford, UK, and presented August 29 at the 2017 European Society of Cardiology Congress in Barcelona, Spain.
“With over 100,000 incident VTE events, we were able to investigate the impact of elevated BP across its whole spectrum and found that higher blood pressure is associated with lower risk of VTE,” reported researchers led by Kazem Rahimi, DM, MSc, associate professor of Cardiovascular Medicine at the University of Oxford and deputy director of the George Institute.
Although elevated blood pressure is a major risk factor for many arterial vascular events, its impact on VTE hasn’t been well investigated, Dr. Rahimi and colleagues noted. Earlier studies have been limited in size or duration.
For this study, the researchers used data from the UK Clinical Practice Research Datalink, covering a total of 6,613,644 UK adults who had at least one blood pressure measurement. From this cohort, 104,017 people were diagnosed with VTE, defined as pulmonary embolism or deep vein thrombosis. The researchers used Cox proportional hazard models to estimate multivariate-adjusted hazard ratios (HR) with floating absolute risks.
Results showed that during a median follow-up of 9.6 years, each 20 mm Hg of higher systolic blood pressure was associated with a 20% lower risk of VTE (HR: 0.80; 95% confidence interval [CI]: 0.79-0.81) and each 10 mm Hg of higher diastolic blood pressure was associated with a 17% lower VTE risk (HR: 0.83; CI: 0.81-0.84). Hypertension (defined as 140/90 mm Hg and higher) was associated with an 18% lower risk of VTE incidence (adjusted HR: 0.82; CI: 0.81-0.84).
“The observed associations were stronger among younger patient groups,” Dr. Rahimi and colleagues also reported.
Why is higher blood pressure linked to lower risk of VTE?
The researchers didn’t speculate, but further studies might provide answers. “Meta-analysis of blood pressure lowering trials could potentially investigate the causal role of low BP on future risk of VTE,” they recommended.