Background: The commonest cause of epilepsy in the elderly is symptomatic vascular brain injury. As the population ages, the prevalence of stroke is projected to rise, and so conceivably the incidence of seizures will increase as well. However, the extent to which individuals presenting with a seizure have a co-morbid diagnosis of stroke and precisely how this relationship varies by age, gender, and race is unclear.
Objective: To assess the relation of admission for an epileptic event with a co-morbid diagnosis of stroke.
Methods: Using the National Inpatient Sample, a nationally representative data set of US hospital admissions, we assessed patients aged 18 years or older hospitalized with seizures who had a comorbid diagnosis of stroke from 2004-2009. We define seizure or epilepsy hospitalizations using primary ICD-9 discharge diagnosis codes 345.0-345.5, 345.7-345.9, and 780.39. Secondary discharge codes for stroke used were 433-437.10, 437.3, and 437.5-438. The sample was stratified into age-categories (75 years), and racial categories. Frequencies and descriptive analysis of comorbidities and confounders were utilized. A logistic regression model was used to further explore the relationship. All analysis were survey-weighted.
Results: During the study period, 253,778 adults (0.64%) of the sample were hospitalized for seizures. On survey-weighted analysis, 11.1% of those hospitalized for seizures had a co-morbid diagnosis of stroke. Among patients with seizures and co-morbid stroke, 23.6% were aged 75 years, 51.6% were women, and 60.7% were of White race. Greater odds of hospitalization for seizures were seen with those with co-morbid stroke vs. no stroke (OR 3.68; 95% CI 3.49-3.89, p<0.01), and blacks (OR 1.45; 95% CI 1.38, 1.52), relative to whites. Females were less likely to be hospitalized for seizure than males (OR 0.63; 95% CI 0.62, 0.65) significant interaction between comorbid stroke, and gender (p<0.01 ).
Conclusions: One out of eleven patients hospitalized with seizures in the United States has a co-morbid diagnosis of stroke. Patients with co-morbid stroke are almost 4 times more likely to hospitalized with seizures than those without known stroke, with gender modifying this relationship.