Prospective study of apolipoprotein E genotype and functional outcome following ischemic stroke.

BACKGROUND The apolipoprotein E (APOE) epsilon 4 allele is a marker of adverse outcome following head injury and intracerebral hemorrhage. Transgenic animal data in a focal cerebral ischemia model suggest that the epsilon 4 allele increases infarct size and functional impairment. OBJECTIVE To determine if APOE genotype is associated with functional recovery from ischemic stroke. DESIGN Prospective study. SETTING Stroke service at a university teaching hospital. PATIENTS Patients with clinical and neuroimaging findings (computed tomography or magnetic resonance imaging) compatible with an acute ischemic stroke. MAIN OUTCOME Functional outcome by Barthel index (BI) and modified Rankin scale (mRS) was compared for epsilon 3/epsilon 3 patients vs epsilon 4 carriers and vs epsilon 2 carriers at 1 and 3 months. Univariate predictors of 3-month outcome were examined in a multivariate analysis. RESULTS One hundred eighty nine patients were enrolled: 100 women, 89 men (mean +/- SD age, 69.4 +/- 11.0 years). There were 25 epsilon 2 alleles (frequency, 0.07), 292 epsilon 3 alleles (0.77), and 61 epsilon 4 alleles (0.16). Baseline National Institutes of Health Stroke Scale scores and Oxfordshire Community Stroke Project classifications were similar in all groups (epsilon 3/epsilon 3, epsilon 4, and epsilon 2 carriers). One-month (BI, P = .64; mRS, P = .59) and 3-month (BI, P = .87; mRS, P = .73) outcomes were not associated with possession of either epsilon 4 or the epsilon 2 allele. Baseline National Institutes of Health Stroke Scale scores (P < .001) and age (P = .002) were significant predictors of 3-month BI and mRS outcomes in multivariate analyses. CONCLUSIONS Although there is a robust influence of APOE polymorphism on functional recovery after some types of brain injury in humans, it does not exert a major influence on injury severity or functional recovery following ischemic stroke. Arch Neurol. 2000;57:1480-1484