The risk of new-onset epilepsy and refractory epilepsy in older adult stroke survivors.

Objective: Our study objectives were to identify factors associated with new-onset epilepsy and refractory epilepsy among older adult stroke survivors and to evaluate the receipt of diagnostic care and mortality for participants who developed epilepsy.

Methods: We conducted a population-based, retrospective cohort study using linked, administrative health care databases. The Ontario Stroke Registry was used to identify patients 67 years and older who were hospitalized for a stroke at a designated stroke center in Ontario, Canada, between April 1, 2003, and March 31, 2009, and were previously free of epilepsy. Multivariable Fine-Gray hazard models were used to examine risk factors of epilepsy and refractory epilepsy, accounting for the competing risk of death.

Results: Among 19,138 older adults hospitalized for a stroke, 210 (1.1%) developed epilepsy and 27 (12.9%) became refractory to antiepileptic drugs. Within 1 year of epilepsy diagnosis, 24 (11.4%) patients were assessed with EEG and 19 (9.0%) with MRI. In multivariable analysis, younger age and thrombolysis receipt significantly increased epilepsy risk. Lesser stroke severity and anticoagulant medication receipt also significantly increased epilepsy risk; however, these effects decreased over time. Younger age and female sex were the only risk factors of refractory epilepsy. In the 5 years following epilepsy diagnosis, 97 (46.2%) participants died of any cause.

Conclusions: Older adult stroke survivors are less likely to develop epilepsy and pharmacologically refractory epilepsy. An estimated 86.6% of deaths among older adult stroke survivors with new-onset epilepsy are attributed to causes other than stroke or epilepsy.