title: Outcomes after acute ischemic stroke in patients with thrombocytopenia or thrombocytosis.
abstract: BACKGROUND
  Thrombocytopenia may be associated with a greater risk of cerebral hemorrhage and thrombocytosis may be associated with a greater risk of cerebral thrombosis. There is a paucity of studies focused on the potential association between blood platelet count (BPC) and outcomes after acute ischemic stroke (AIS). We hypothesized that abnormal BPC is associated with poorer outcomes after AIS.
  
  
  METHODS
  This study included data from the Ontario Stroke Registry on consecutive patients with AIS admitted between July 2003 and March 2008. Patients were divided into groups as follows: low BPC (<150,000/mm(3)), normal BPC (150,000 to 450,000/mm(3)) and high BPC (>450,000/mm(3)). Primary outcome measures were the frequency of moderate/severe strokes on admission (Canadian Neurologic Scale: <8), greater degree of disability at discharge (modified Rankin score: 3-6), and 30-day and 90-day mortality.
  
  
  RESULTS
  We included 9230 patients. Both low and high BPC were associated with higher 30-day mortality (p≤0.0335) and 90-day mortality (p≤0.048) following AIS. The Kaplan-Meier curves indicate that abnormal BPC is associated with greater mortality after AIS (p=0.0002). Nonetheless, abnormal BPC was not associated with initial stroke severity (p≥0.225), degree of disability (p≥0.3761), or length of stay in the acute stroke care center (p≥0.7818) after adjustment for major potential confounders.
  
  
  CONCLUSIONS
  Thrombocytopenia and thrombocytosis on the initial admission are associated with higher mortality after AIS. Abnormal BPC does not adversely affect the degree of initial impairment, disability at discharge, or length of stay in the acute care hospital after AIS.
authors.affiliation: Department of Medicine, Division of Neurology, University of Toronto, Toronto, Ontario, Canada, M4G 3V9; Department of Medicine, Division of Physical Medicine and Rehabilitation, Lyndhurst Centre, Toronto, Ontario, Canada, M4G 3V9; Lyndhurst Centre, Toronto Rehabilitation Institute, University Health Network, Toronto, Ontario, Canada, M4G 3V9. Electronic address: jcfurlan@gmail.com.
authors.forename: Julio C
authors.initials: JC
authors.lastname: Furlan
authors.affiliation: Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada, M4G 3V9.
authors.forename: Jiming
authors.initials: J
authors.lastname: Fang
authors.affiliation: Department of Medicine, Division of Neurology, University of Toronto, Toronto, Ontario, Canada, M4G 3V9; Institute for Clinical Evaluative Sciences, Toronto, Ontario, Canada, M4G 3V9; Division of Neurology, University Health Network, Toronto, Ontario, Canada, M4G 3V9.
authors.forename: Frank L
authors.initials: FL
authors.lastname: Silver
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D015331:Cohort Studies; D005260:Female; D015600:Glasgow Coma Scale; D006801:Humans; D008297:Male; D008875:Middle Aged; D017063:Outcome Assessment, Health Care; D010976:Platelet Count; D012372:ROC Curve; D020521:Stroke / Q000150:complications*; D013921:Thrombocytopenia / Q000209:etiology*; D013922:Thrombocytosis / Q000209:etiology*; D013997:Time Factors
keywords: Disability; Impairment; Mortality; Platelets; Stroke; Thrombocytopenia; Thrombocytosis