P4817The individual stroke risk in patients with atrial fibrillation

Introduction: In patients with atrial fibrillation (AF), the CHA2DS2-VASc score is used to assess the risk of stroke and guide the need for anticoagulation. However, the CHA2DS2-VASc score combines low and high-risk patients and uncertainty exist of whether patients with a score of one should be anticoagulated. Purpose: To assess the individual risk of stroke from all the combinations of the CHA2DS2-VASc score. Methods: Patients with AF without prior anticoagulation from 1997–2014 were included to examine the 1-year absolute risk of stroke. A multiple logistic regression model was fitted, including patient age, calendar year, and the CHA2DS2-VASc score risk factors. Presented are individual 1-year absolute risk predictions of the patients obtained by estimating the model. Results: A total of 138,295 patients with AF were included in the study (median age = 76 years, 51% females). The absolute 1-year risk of stroke varied greatly for the CHA2DS2-VASc scores. Importantly, both the scores zero (perceived low risk) and one (intermediate risk) included patients with an absolute risk above the suggested threshold of stroke risk of 0.9% per year, and CHA2DS2-VASc scores up to five included patients with an absolute stroke risk under 0.9% (Table). To predict the individual stroke risk for all the combinations of the CHA2DS2-VASc score an online calculator is available.