title: The apolipoprotein E epsilon4 allele and outcome in cerebrovascular disease.
abstract: OBJECTIVE
  Polymorphism of the apolipoprotein E gene (APOE) may influence outcome after traumatic brain injury and intracerebral hemorrhage, with the epsilon4 allele being associated with poorer prognosis. We investigated APOE allele distribution in acute stroke and the effect of the epsilon4 allele on outcome.
  
  
  METHODS
  APOE genotypes were determined in 714 stroke patients: 640 ischemic stroke and 74 intracerebral hemorrhage patients. The survival effect of the epsilon4 allele was assessed with the use of a stratified log-rank test. A Cox proportional hazards regression model was used to estimate the independent effect of epsilon4 dose (0, 1, or 2) on survival, and logistic regression was used to determine the effect on 3-month outcome (good if alive at home, poor if in care or dead).
  
  
  RESULTS
  Allele distribution matched the general population with no difference between the ischemic and hemorrhagic groups. Survival in the entire cohort was unaffected by epsilon4 dose. Improved survival with increasing epsilon4 dose was found in the ischemic group (relative hazard=0.76 per allele; P=0.04). If transient ischemic attacks were excluded, a trend for improved survival persisted (P=0.06). With intracerebral hemorrhage, a trend was seen toward reduced survival with epsilon4 (P=0.07, log-rank test). Three-month outcome in the ischemic group was unaffected by epsilon4 dose, and a trend toward poorer outcome with epsilon4 was seen for intracerebral hemorrhage (P=0.10).
  
  
  CONCLUSIONS
  The APOE epsilon4 allele had divergent effects on survival and outcome in ischemic and hemorrhagic strokes in this population. The reported adverse effect on patients with intracerebral hemorrhage was supported. The favorable survival effect on ischemic stroke patients requires further study.
authors.affiliation: Department of Neuropathology, Institute of Neurological Sciences, Southern General Hospital, Glasgow, Scotland, UK.
authors.forename: M O
authors.initials: MO
authors.lastname: MCarron
authors.forename: K W
authors.initials: KW
authors.lastname: Muir
authors.forename: C J
authors.initials: CJ
authors.lastname: Weir
authors.forename: A G
authors.initials: AG
authors.lastname: Dyker
authors.forename: I
authors.initials: I
authors.lastname: Bone
authors.forename: J A
authors.initials: JA
authors.lastname: Nicoll
authors.forename: K R
authors.initials: KR
authors.lastname: Lees
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000483:Alleles; D053327:Apolipoprotein E4; D001057:Apolipoproteins E / Q000235:genetics*; D002545:Brain Ischemia / Q000150:complications / Q000235:genetics / Q000401:mortality; D002543:Cerebral Hemorrhage / Q000150:complications / Q000235:genetics / Q000401:mortality; D002561:Cerebrovascular Disorders / Q000209:etiology / Q000235:genetics* / Q000401:mortality*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D011110:Polymorphism, Genetic; D011379:Prognosis; D016019:Survival Analysis
chemical_list: D053327:Apolipoprotein E4; D001057:Apolipoproteins E