Prevalence, predictors, and prognosis of mortality among elderly stroke patients with convulsive status epilepticus in the United States

Background: Stroke is the most common cause of epilepsy in the elderly. However, despite the high mortality typically associated with convulsive status epilepticus (CSE), there is a dearth of nationwide data on the magnitude and association of CSE with mortality among hospitalized elderly with stroke in the United States. Methods: We analyzed the 2006–2014 National Inpatient Sample (NIS) to identify elderly patients (65+ years) with a primary discharge diagnosis of stroke using the International Classification of Diseases, Ninth Revision-Clinical Modification (ICD-9-CM) codes 433.X1, 434.X1, 436, 430, 431, 432.0, 432.1, and 432.9. We examined a subgroup with a secondary discharge diagnosis of convulsive status epilepticus (ICD-9-CM: 345.3). We estimated the hospital mortality rate by CSE status and then evaluated the independent association of CSE and other key factors with mortality among hospitalized elderly with stroke. Results: A total of 1220 elderly patients (0.14%) had a secondary discharge diagnosis of CSE. Inpatient mortality rate was 25.8% among those with CSE vs. 7.7% for non-CSE patients. CSE was independently associated with a 4-fold increased odds of in-hospital death. Increased age, medical comorbidities, weekend admissions, being a Medicare beneficiary, and hospitalization in large urban teaching hospitals were also independently associated with a greater likelihood of in-hospital death. The small number of events did not allow analysis by stroke subtypes. Conclusion: While CSE occurs in just 14 of 10,000 hospitalized elderly stroke patients in the United States, it is associated with a 4-fold higher odds of in-hospital death.