Usefulness of the CHADS2 Score for Determining Risk of Seizure in Patients With Atrial Fibrillation.

Atrial fibrillation (AF) secondary to seizure has been described in case reports, but the association between AF and risk of seizure has never been evaluated in longitudinal studies. The objectives of this study were to investigate the role of AF on the risk of development of seizure and the usefulness of CHADS2 score for predicting the risk of seizure. Our analyses were conducted using information from a random sample of 1 million subjects enrolled in Taiwan National Health Insurance Research Database. A total of 11,552 subjects aged ≥18 years, comprising 5,776 subjects diagnosed with AF during the study period and 5,776 age and sex-matched subjects without AF were enrolled in our study. During the mean follow-up of 6.7 ± 3.3 years, seizure events occurred in 235 patients. In comparison, the AF group had a higher incidence rate of seizure occurrence (4.17 vs 1.90 per 1,000 person-years). Cox proportional hazard regression model analysis showed that development of AF was independently associated with a higher risk of developing future seizure (adjusted HR 2.30; 95% confidence interval 1.73 to 3.05). In multivariate Cox regression analysis adjusted for potentially confounding variables, a higher CHADS2 score was associated with a higher risk of seizure in a dose-dependent manner. AF may cause an ischemic stroke that subsequently leads to seizure, and present study further demonstrates that AF patients are associated with higher rate of subsequent seizure, even after adjusting for stroke. The CHADS2 score was found to be a useful scheme for predicting the risk of seizure occurrence.