Sørensen HT, Horvath-Puho E, Christensen S, Pedersen L, Prandoni P, Baron JA.; J Thromb Haemost. 2010 May 12.
Background: Venous thromboembolism is a predictor of subsequent risk of ischaemic stroke and intracerebral haemorrhage, but no data are available regarding its association with risk of subarachnoid haemorrhage.
Objectives: To examine this issue, we conducted a nationwide cohort study in Denmark.
Patients and methods: We identified 97 558 patients with a hospital diagnosis of venous thromboembolism between 1977 and 2007 and obtained information on risk of subsequent subarachnoid haemorrhage during follow-up in the Danish Registry of Patients. The incidence of subarachnoid haemorrhage in the venous thromboembolism cohort was compared with that of 453 406 population control cohort members.
Results For patients with pulmonary embolism, there was a clearly increased risk of subarachnoid haemorrhage, both during the first year of follow-up (relative risk 2.69; 95% confidence interval (CI), 1.32 – 5.48) and during later follow-up of 2 to 20 years (relative risk 1.40; 95% CI, 1.05 -1.87). For patients with deep venous thrombosis the risk was likewise clearly increased during the first year of follow-up (relative risk 1.91 (95% CI, 1.13 – 3.22), but not during later follow-up (relative risk 1.04; 95% CI, 0.81 -1.32).
Conclusions We found evidence that pulmonary embolism is associated with an increased long-term risk of subarachnoid haemorrhage. The two diseases might share etiologic pathways affecting the vessel wall or share unknown risk factors.
Weblink here