title: The increasing incidence of anticoagulant-associated intracerebral hemorrhage.
abstract: OBJECTIVE
  To define temporal trends in the incidence of anticoagulant-associated intracerebral hemorrhage (AAICH) during the 1990s and relate them to rates of cardioembolic ischemic stroke.
  
  
  METHODS
  We identified all patients hospitalized with first-ever intracerebral hemorrhage (ICH) in greater Cincinnati during 1988, from July 1993 through June 1994, and during 1999. AAICH was defined as ICH in patients receiving warfarin or heparin. Patients from the same region hospitalized with first-ever ischemic stroke of cardioembolic mechanism were identified during 1993/1994 and 1999. Incidence rates were calculated and adjusted to the 2000 US population. Estimates of warfarin distribution in the United States were obtained for the years 1988 through 2004.
  
  
  RESULTS
  AAICH occurred in 9 of 184 ICH cases (5%) in 1988, 23 of 267 cases (9%) in 1993/1994, and 54 of 311 cases (17%) in 1999 (p < 0.001). The annual incidence of AAICH per 100,000 persons was 0.8 (95% CI 0.3 to 1.3) in 1988, 1.9 (1.1 to 2.7) in 1993/1994, and 4.4 (3.2 to 5.5) in 1999 (p < 0.001 for trend). Among persons aged > or =80, the AAICH rate increased from 2.5 (0 to 7.4) in 1988 to 45.9 (25.6 to 66.2) in 1999 (p < 0.001 for trend). Incidence rates of cardioembolic ischemic stroke were similar in 1993/1994 and 1999 (31.1 vs 30.4, p = 0.65). Warfarin distribution in the United States quadrupled on a per-capita basis between 1988 and 1999.
  
  
  CONCLUSIONS
  The incidence of anticoagulant-associated intracerebral hemorrhage quintupled in our population during the 1990s. The majority of this change can be explained by increasing warfarin use. Anticoagulant-associated intracerebral hemorrhage now occurs at a frequency comparable to subarachnoid hemorrhage.
authors.affiliation: Department of Neurology, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0525, USA. matthew.flaherty@uc.edu
authors.forename: M L
authors.initials: ML
authors.lastname: Flaherty
authors.forename: B
authors.initials: B
authors.lastname: Kissela
authors.forename: D
authors.initials: D
authors.lastname: Woo
authors.forename: D
authors.initials: D
authors.lastname: Kleindorfer
authors.forename: K
authors.initials: K
authors.lastname: Alwell
authors.forename: P
authors.initials: P
authors.lastname: Sekar
authors.forename: C J
authors.initials: CJ
authors.lastname: Moomaw
authors.forename: M
authors.initials: M
authors.lastname: Haverbusch
authors.forename: J P
authors.initials: JP
authors.lastname: Broderick
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000925:Anticoagulants / Q000600:supply & distribution* / Q000627:therapeutic use*; D002545:Brain Ischemia / Q000453:epidemiology*; D002543:Cerebral Hemorrhage / Q000453:epidemiology*; D015897:Comorbidity; D005260:Female; D006801:Humans; D015994:Incidence; D007629:Kentucky / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D009820:Ohio / Q000453:epidemiology; D012189:Retrospective Studies; D018570:Risk Assessment / Q000379:methods; D012307:Risk Factors; D020521:Stroke / Q000453:epidemiology*; D014481:United States; D014859:Warfarin / Q000600:supply & distribution* / Q000627:therapeutic use*
chemical_list: D000925:Anticoagulants; D014859:Warfarin