Venous thromboembolisms and stroke risk in patients with atrial fibrillation: a nationwide cohort study

Little is known about the association of venous thromboembolisms (VTEs) on the risk of ischaemic stroke (IS) in patients with atrial fibrillation (AF). Nevertheless, both pulmonary embolism (PE) and deep venous thromboembolism (DVT) are often included in the calculation of the CHA₂DS₂-VASc score, which is used for stroke risk stratification. Therefore, we conducted this nationwide retrospective cohort study to evaluate whether a history of VTE is associated with an increased risk of IS in patients with AF.

The Finnish AntiCoagulation in Atrial Fibrillation (FinACAF) registry-linkage study includes all patients in Finland with incident AF from 2007 to 2018. The IS rates and rate ratios were computed for patients with and without a history of VTE. We identified 271 500 patients with new-onset AF, of whom 4.6% had prior VTE, while 1.9% had a history of PE and 3.1% a history of DVT. The crude incidence of IS was slightly higher in patients with a history of VTE compared to patients without a history of VTE, but after adjusting for baseline factors, VTE was not associated with the rate of IS [adjusted incidence rate ratio with 95% confidence interval for any VTE 1.05 (0.98–1.13), for PE 1.01 (0.91–1.13), and for DVT 1.09 (1.00–1.18)]. There was no temporal change in these associations during the study period.

A history of VTEs was not associated with an increased risk of IS, suggesting that they do not need to be considered in the stroke risk stratification of patients with AF.