Comparing the risk of subsequent ischemic stroke and mortality in patients with epilepsy and patients with ischemic stroke

Patients with stroke or epilepsy face an elevated risk of subsequent strokes. This nationwide retrospective cohort study analyzed data from Taiwan's National Health Insurance Research Database (2012-2020) to compare the risk of future ischemic stroke or transient ischemic attack (IS/TIA) among patients with epilepsy and those with prior IS/TIA. Patients were categorized into four groups: epilepsy with subsequent IS/TIA (E/S), epilepsy without IS/TIA (E), IS/TIA without epilepsy (S), and neither condition (C). Incidence rates and adjusted hazard ratios for IS/TIA and mortality were assessed across groups, which included 5,606, 11,212, 11,212, and 56,060 patients. The corresponding incidence rates of subsequent IS/TIA were 0.67, 0.03, 0.41, and 0.01 per 100 person-years in the E/S, E, S, and C groups, respectively. Compared to the S group, the E/S group had a higher adjusted hazard ratio for IS/TIA (aHR 1.68, 95% CI: 1.30-2.17), whereas the E group had a significantly lower adjusted hazard ratio (aHR 0.08, 95% CI: 0.04-0.14). Mortality risk was significantly elevated in both the E/S group (aHR 1.90, 95% CI: 1.75-2.05) and the E group (aHR 1.21, 95% CI: 1.12-1.30), compared to the S group. These findings suggest that epilepsy increases the risk of subsequent IS/TIA, though to a lesser extent than prior IS/TIA. They underscore the importance of condition-specific prevention strategies and the need for further research into the mechanisms linking epilepsy and stroke risk.