Family history increases the risk of late seizures after stroke

To assess the association between a family history of epilepsy and risk of late poststroke seizures (LPS).

This register-based cohort study was based on adult patients from the Swedish Stroke Register (Riksstroke) with stroke from 2001 to 2012 and no prior epilepsy. LPS (>7 days after stroke) and epilepsy were ascertained in cases and in their first-degree biological relatives by cross-referencing Riksstroke, the Multi-Generation Register, and the National Patient Register.

Of 86,550 patients with stroke, a family history of epilepsy was detected in 7,433 (8.6%), and LPS (>7 days after stroke) occurred in 7,307 (8.4%). The survival-adjusted risk of LPS was higher in patients with compared to those without a family history of epilepsy: 6.8% (95% confidence interval [CI] 6.2%-7.4%) vs 5.9% (95% CI 5.7%-6.1%) at 2 years and 9.5% (95% CI 8.7%-10.3%) vs 8.2% (95% CI 8.0%-8.4%) at 5 years. In a Cox model adjusted for age, sex, and stroke type, the hazard ratio (HR) for LPS in patients with stroke with ≥1 relative with epilepsy was 1.18 (95% CI 1.09-1.28). The increased HR remained significant with adjustments for stroke severity and in multiple sensitivity analyses. A higher risk for patients with stroke with >1 relative with epilepsy was also seen but was not significant in all Cox models.

Although stroke characteristics remain the most important risk factors for LPS, having a first-degree relative with epilepsy also increases the risk in a multivariate analysis. The findings highlight the need for family history assessment in patients with stroke and the need for future studies on genetic vulnerability and environmental factors that may aid in the identification of at-risk individuals.