title: Transient global amnesia and the risk of ischemic stroke.
abstract: OBJECTIVE
  Whether transient global amnesia (TGA) represents an arterial insult that heralds ischemic stroke remains unclear. Therefore, we examined stroke risk after TGA in a population-based cohort.
  
  
  METHODS
  After performing chart review at our institution to validate the International Classification of Diseases, 9th Edition, Clinical Modification diagnosis code for TGA, we used administrative claims data to identify all patients discharged from nonfederal California emergency departments or acute care hospitals between 2005 and 2010 with a primary discharge diagnosis of TGA. Patients with a primary discharge diagnosis of migraine, seizure, or transient ischemic attack were included as controls. Kaplan-Meier statistics were used to calculate rates of ischemic stroke, and Cox proportional hazards analyses were used to compare stroke risk among the 4 exposure groups while controlling for traditional stroke risk factors.
  
  
  RESULTS
  International Classification of Diseases, 9th Edition, Clinical Modification code 437.7 had a sensitivity of 86% and a specificity of 95% for TGA. The cumulative 1-year rate of stroke was 0.54% (95% confidence interval [CI], 0.36-0.81) after TGA, 0.22% (95% CI, 0.20-0.25) after migraine, 0.90% (95% CI, 0.83-0.97) after seizure, and 4.72% (95% CI, 4.60-4.85) after transient ischemic attack. After adjustment for demographic characteristics and stroke risk factors, TGA was not associated with stroke risk when compared with migraine (hazard ratio, 0.82; 95% CI, 0.61-1.10). The likelihood of stroke after TGA was lower than after seizure (hazard ratio, 0.57; 95% CI, 0.44-0.76) or transient ischemic attack (hazard ratio, 0.27; 95% CI, 0.20-0.35).
  
  
  CONCLUSIONS
  Compared with patients diagnosed with migraine or seizure, patients diagnosed with TGA do not seem to face a heightened risk of stroke.
authors.affiliation: From the Department of Neurology and the Brain and Mind Research Institute, Weill Cornell Medical College, New York, NY.
authors.forename: Atul
authors.initials: A
authors.lastname: Mangla
authors.forename: Babak B
authors.initials: BB
authors.lastname: Navi
authors.forename: Kelly
authors.initials: K
authors.lastname: Layton
authors.forename: Hooman
authors.initials: H
authors.lastname: Kamel
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D020236:Amnesia, Transient Global / Q000453:epidemiology*; D002140:California / Q000453:epidemiology; D015331:Cohort Studies; D016001:Confidence Intervals; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D038801:International Classification of Diseases; D002546:Ischemic Attack, Transient / Q000150:complications / Q000453:epidemiology; D008297:Male; D008875:Middle Aged; D008881:Migraine Disorders / Q000150:complications / Q000453:epidemiology; D011379:Prognosis; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012640:Seizures / Q000150:complications / Q000453:epidemiology; D020521:Stroke / Q000453:epidemiology*; D016896:Treatment Outcome
keywords: amnesia, transient global; stroke