title: Long-term hemorrhage risk in children versus adults with brain arteriovenous malformations.
abstract: OBJECTIVE
  Children with brain arteriovenous malformations (BAVMs) are said to be at higher risk for intracranial hemorrhage (ICH) than adults. Although this notion affects treatment decisions, the evidence to support this claim is limited.
  
  
  METHODS
  To compare the risk of ICH in children versus adults with BAVM, we studied all cases of BAVM evaluated at the University of California, San Francisco (January 2000 to December 2004; n=400) and Kaiser Permanente Northern California (January 1993 to December 2004; n=819). In Kaplan-Meier survival analyses, the index date was the date of initial BAVM detection; cases were censored at time of subsequent ICH (the primary outcome, defined as ICH after initial presentation), first BAVM treatment, or loss to follow-up. Cox proportional hazards models included childhood presentation (<20 years old), hemorrhagic presentation, and other potential confounders.
  
  
  RESULTS
  Our study included 996 person-years of follow-up in the childhood presentation group and 3260 in the adult presentation group. In the unadjusted survival analysis, the subsequent ICH rates were similar for the 2 age groups (average annual rate 2.0% for children; 2.2% for adults; P=0.82 by log-rank test). BAVMs in childhood were more likely to present initially with ICH (P<0.001). After adjustment for presentation in the multivariate model, subsequent ICH rates were lower in children (hazard ratio, 0.10; 95% CI, 0.01 to 0.86; P=0.036).
  
  
  CONCLUSIONS
  Children with BAVMs do not appear to be at increased risk for a subsequent ICH compared with adults, and may even be relatively protected. Confounding by hemorrhagic presentation should be considered in any study comparing BAVM hemorrhage rates in children versus adults.
authors.affiliation: Department of Neurology, University of California, San Francisco, CA 94143-0137, USA. fullertonh@neuropeds.ucsf.edu
authors.forename: Heather J
authors.initials: HJ
authors.lastname: Fullerton
authors.forename: Achal S
authors.initials: AS
authors.lastname: Achrol
authors.forename: S Claiborne
authors.initials: SC
authors.lastname: Johnston
authors.forename: Charles E
authors.initials: CE
authors.lastname: McCulloch
authors.forename: Randall T
authors.initials: RT
authors.lastname: Higashida
authors.forename: Michael T
authors.initials: MT
authors.lastname: Lawton
authors.forename: Stephen
authors.initials: S
authors.lastname: Sidney
authors.forename: William L
authors.initials: WL
authors.lastname: Young
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D000368:Aged; D002543:Cerebral Hemorrhage / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology*; D002648:Child; D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D002538:Intracranial Arteriovenous Malformations / Q000150:complications* / Q000175:diagnosis / Q000453:epidemiology / Q000473:pathology; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D016016:Proportional Hazards Models; D012306:Risk; D012680:Sensitivity and Specificity; D017741:Survivors; D013997:Time Factors; D016896:Treatment Outcome