title: Meta-analysis of APOE genotype and subarachnoid hemorrhage: clinical outcome and delayed ischemia.
abstract: BACKGROUND
  Emerging evidence suggests that the APOE4 allele may increase the risk of a negative outcome in patients with aneurysmal subarachnoid hemorrhage (SAH), but the results are conflicting. A genetic variable predicting the individual clinical course is currently lacking.
  
  
  OBJECTIVE
  To examine the association between the APOE4 allele and a negative outcome. A secondary objective was to investigate the association between the APOE4 allele and delayed ischemia, a major complication of SAH.
  
  
  METHODS
  We searched MEDLINE, EMBASE, the Cochrane Library, CINHAL, LILACS, and www.google.it through March 2006. We hand-searched journals, international conference proceedings, and reference lists of retrieved articles. Individual patient data were requested from the corresponding authors of the original articles. Information on study design, participant characteristics, clinical outcome, delayed ischemia, and confounder distribution were independently abstracted by two investigators.
  
  
  RESULTS
  We included eight observational studies (696 patients for the clinical outcome and 600 for the delayed ischemia analyses). The corresponding authors of all the retrieved publications but one gave their original data. Summary odds ratios (ORs) were calculated by means of the random-effect model. The risk of a negative outcome (OR = 2.558; 95% CI 1.610 to 4.065) and delayed ischemia (OR = 2.044; 95% CI 1.269 to 3.291) were increased in the E4 carriers.
  
  
  CONCLUSIONS
  In patients with subarachnoid hemorrhage, the expression of the E4 allele is associated with a higher risk of a negative outcome and delayed ischemia.
authors: Department of Neurosurgery, Ospedali Riuniti, Bergamo, Italy. l.lanterna@virgilio.it
authors: L A
authors: LA
authors: Lanterna
authors: Y
authors: Y
authors: Ruigrok
authors: S
authors: S
authors: Alexander
authors: J
authors: J
authors: Tang
authors: F
authors: F
authors: Biroli
authors: L T
authors: LT
authors: Dunn
authors: W S
authors: WS
authors: Poon
mesh_terms: D053327:Apolipoprotein E4 / Q000235:genetics*; D001921:Brain / Q000098:blood supply / Q000378:metabolism* / Q000503:physiopathology; D001923:Brain Chemistry / Q000235:genetics*; D002545:Brain Ischemia / Q000209:etiology / Q000235:genetics* / Q000503:physiopathology; D004252:DNA Mutational Analysis; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics*; D005820:Genetic Testing; D005838:Genotype; D006579:Heterozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D011237:Predictive Value of Tests; D011379:Prognosis; D012307:Risk Factors; D013345:Subarachnoid Hemorrhage / Q000150:complications*; D013997:Time Factors
chemical_list: D053327:Apolipoprotein E4; D005819:Genetic Markers