Abstract 109: The Long-Term Risk of Seizures After Stroke

Abstract

Introduction: Few data exist on the long-term risk of seizures after stroke. Hypothesis: Stroke is associated with a similar long-term risk of seizures as compared with traumatic brain injury (TBI), a well-established long-term seizure risk factor. Methods: Using administrative claims data on all acute care hospitalizations and emergency department (ED) visits at nonfederal facilities in California, Florida, and New York from 2005-2012, we identified patients at the time of a first documented stroke. Stroke was comprised of ischemic stroke, intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH), as defined by previously validated ICD-9-CM codes. As a control group, we identified patients at the time of a first documented TBI. The primary outcome was an ED visit or hospitalization with a discharge diagnosis of seizure. In sensitivity analyses, we limited the outcome to primary discharge diagnoses of seizure or diagnoses of status epilepticus. Survival statistics and Cox proportional hazards analysis was used to compare the rates and hazard of seizures between groups while adjusting for demographic characteristics and Elixhauser comorbidities. Results: We identified 568,659 patients with stroke and 270,796 patients with TBI. During 2.5 (±2.1) years of follow-up, the cumulative risk of a seizure was 37.6% (95% confidence interval [CI], 37.3-37.8%) in patients with stroke and 29.9% (95% CI, 29.5-30.0%) in patients with TBI. After adjustment for demographic characteristics and comorbidities, stroke remained associated with a slightly higher hazard of seizures when compared with the risk after TBI (hazard ratio [HR], 1.12; 95% CI, 1.11-1.13). This finding was unchanged in sensitivity analyses of only primary discharge diagnoses of seizure or only status epilepticus cases. In subgroup analyses, the cumulative rate of any seizure was 26.2% (95% CI, 25.6-26.9%) after SAH, 33.6% (95% CI, 33.4-33.7%) after ischemic stroke, and 35.0% (95% CI, 34.5-35.4%) after ICH. Conclusions: We found that a substantial proportion of patients with stroke develop a seizure. The long-term risk of seizure after stroke appears similar to that after TBI, which is widely recognized as a strong long-term seizure risk factor.