Population-Based Assessment of the Long-term Risk of Seizures in Survivors of Stroke

Alexander E. Merkler, MD; Gino Gialdini, MD; Michael P. Lerario, MD; Neal S. Parikh, MD; Nicholas A. Morris, MD; Benjamin Kummer, MD; Lauren Dunn, MD; Michael E. Reznik, MD; Santosh B. Murthy, MD, MPH; Babak B. Navi, MD, MS; Zachary M. Grinspan, MD, MS; Costantino Iadecola, MD; Hooman Kamel, MD

Disclosures

Stroke. 2018;49(6):1319-1324. 

In This Article

Abstract and Introduction

Abstract

Background and Purpose: We sought to determine the long-term risk of seizures after stroke according to age, sex, race, and stroke subtype.

Methods: We performed a retrospective cohort study using administrative claims from 2 complementary patient data sets. First, we analyzed data from all emergency department visits and hospitalizations in California, Florida, and New York from 2005 to 2013. Second, we evaluated inpatient and outpatient claims from a nationally representative 5% random sample of Medicare beneficiaries. Our cohort consisted of all adults at the time of acute stroke hospitalization without a prior history of seizures. Our outcome was seizure occurring after hospital discharge for stroke. Poisson regression and demographic data were used to calculate age-, sex-, and race-standardized incidence rate ratios (IRR).

Results: Among 777 276 patients in the multistate cohort, the annual incidence of seizures was 1.68% (95% confidence interval [CI], 1.67%–1.70%) after stroke versus 0.15% (95% CI, 0.15%–0.15%) among the general population (IRR, 7.3; 95% CI, 7.3–7.4). By 8 years, the cumulative rate of any emergency department visit or hospitalization for seizure was 9.27% (95% CI, 9.16%–9.38%) after stroke versus 1.21% (95% CI, 1.21%–1.22%) in the general population. Stroke was more strongly associated with a subsequent seizure among patients <65 years of age (IRR, 12.0; 95% CI, 11.9–12.2) than in patients ≥65 years of age (IRR, 5.5; 95% CI, 5.4–5.5) and in the multistate analysis, the association between stroke and seizure was stronger among nonwhite patients (IRR, 11.0; 95% CI, 10.8–11.2) than among white patients (IRR, 7.3; 95% CI, 7.2–7.4). Risks were especially elevated after intracerebral hemorrhage (IRR, 13.3; 95% CI, 13.0–13.6) and subarachnoid hemorrhage (IRR, 13.2; 95% CI, 12.8–13.7). Our study of Medicare beneficiaries confirmed these findings.

Conclusions: Almost 10% of patients with stroke will develop seizures within a decade. Hemorrhagic stroke, nonwhite race, and younger age seem to confer the greatest risk of developing seizures.

Introduction

Stroke occurs in ≈800 000 people annually in the United States and is a leading cause of long-term disability.[1] Seizures commonly occur after stroke and are associated with increased mortality, higher odds of functional decline, and an overall lower quality of life.[2–9] Based on previous population-based studies, estimates of the overall rate of poststroke seizures vary from 2.6% to 13.5%.[2,10–16] It is well-known that seizures can occur in the setting of acute stroke, but the long-term risk of seizures in survivors of stroke remains unclear. Furthermore, although previous studies have suggested a higher risk of seizures after hemorrhagic stroke compared with ischemic stroke, the long-term risk of seizures has not been rigorously assessed by stroke subtype or demographic characteristics.[2,12–14,16–18] We, therefore, designed this study to evaluate the long-term risk of seizures according to age, sex, race, and stroke subtype in patients free of seizures before stroke hospitalization in 2 large, nationally representative cohorts of patients in the United States.

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