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

Results

Multistate Patient Characteristics

We identified 777 276 patients with an acute stroke hospitalization in California, Florida, and New York between 2005 and 2013. Of these strokes, 653 564 (84.1%) were ischemic strokes, 89 173 (11.5%) were ICH and 34 539 (4.4%) were SAH. Median patient follow-up time was 3.9 years (interquartile range, 2.0–5.8). Among patients with stroke, 45 708 (5.88%) developed a seizure; those with subsequent seizures were on average younger than those without subsequent seizures (Table I in the online-only Data Supplement).

Multistate Analysis

The annual incidence of seizures was 1.68% (95% CI, 1.67%–1.70%) in patients with stroke, as compared with 0.15% (95% CI, 0.15%–0.15%) among the general population of California, Florida, and New York (IRR, 7.3; 95% CI, 7.3–7.4; Table 1). By 8 years, the cumulative rate of an emergency department visit or hospitalization for seizure was 9.27% (95% CI, 9.16%–9.38%) after discharge with stroke, as compared with 1.21% (95% CI, 1.21%–1.22%) in the general population. The annual incidence of seizures and the cumulative rate of seizures were highest in patients with hemorrhagic stroke subtypes (Figure 1). Stroke was also associated with our secondary outcome of subsequent status epilepticus resulting in hospitalization (IRR, 10.6; 95% CI, 9.9–11.5).

Figure 1.

Cumulative rate of an emergency department visit or hospitalization for seizures in California, Florida, and New York. Kaplan–Meier curve showing cumulative rates of seizures in patients with ischemic stroke, intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH) as compared with the general population of California, Florida, and New York.

In subgroup analyses, younger patients and nonwhite patients were more likely to develop seizures after stroke (Table 2). Among patients <65 years of age, stroke was more strongly associated with subsequent seizures (IRR, 12.0; 95% CI, 11.9–12.2) than in patients ≥65 years of age where the association between stroke and postdischarge seizures was similar to what we found in the Medicare population (IRR, 5.5; 95% CI, 5.4–5.5; Table 3). A test of interaction confirmed that the association between stroke and seizures varied significantly by age (P<0.001). The association between stroke and seizures 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; Table 2). A test of interaction confirmed that the association between stroke and seizures varied significantly by race (P<0.001). The association between stroke and subsequent seizures was similar among men and women (Table 2).

Medicare Beneficiaries Patient Characteristics

We identified 1 672 886 Medicare beneficiaries of whom 81 984 had an acute stroke hospitalization. Of these strokes, 68 666 (83.7%) were ischemic strokes, 9990 (12.2%) were ICH, and 3328 (4.1%) were SAH. Median patient follow-up time was 5 years (interquartile range, 2.6–6). Among patients with stroke, 4530 (5.53%) developed a seizure; those with subsequent seizures were younger than those without subsequent seizures (Table II in the online-only Data Supplement).

Medicare Claims Analysis

The annual incidence of seizures was 3.45% (95% CI, 3.35%–3.55%) in patients with stroke, as compared with 0.62% (95% CI, 0.61%–0.62%) among the remaining beneficiaries (IRR, 4.1; 95% CI, 3.9–4.2; Table 3). By 6 years, the cumulative rate of seizure was 13.37% (95% CI, 12.70%–14.08%) after discharge with stroke, as compared with 3.42% (95% CI, 3.39%–3.45%) in the remaining beneficiaries. Similar to the multistate analysis, the annual incidence of seizures and the cumulative rate of seizures were highest in patients with hemorrhagic stroke subtypes (Table 3; Figure 2).

Figure 2.

Cumulative rate of seizures in a 5% sample of Medicare beneficiaries. Kaplan–Meier curve showing cumulative rates of seizures in patients with ischemic stroke, intracerebral hemorrhage (ICH), and subarachnoid hemorrhage (SAH) as compared with the remaining beneficiaries.

In subgroup analyses of the Medicare claims data, the association between stroke and subsequent seizures was similar among white versus nonwhite patients and among men and women (Table 4).

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