title: Risk of Intracerebral Hemorrhage after Emergency Department Discharges for Hypertension.
abstract: BACKGROUND
  Recent literature suggests that acute rises in blood pressure may precede intracerebral hemorrhage. We therefore hypothesized that patients discharged from the emergency department with hypertension face an increased risk of intracerebral hemorrhage in subsequent weeks.
  
  
  METHODS
  Using administrative claims data from California, New York, and Florida, we identified all patients discharged from the emergency department from 2005 to 2011 with a primary diagnosis of hypertension (ICD-9-CM codes 401-405). We excluded patients if they were hospitalized from the emergency department or had prior histories of cerebrovascular disease at the index visit with hypertension. We used the Mantel-Haenszel estimator for matched data to compare each patient's odds of intracerebral hemorrhage during days 8-38 after emergency department discharge to the same patient's odds during days 373-403 after discharge. This cohort-crossover design with a 1-week washout period enabled individual patients to serve as their own controls, thereby minimizing confounding bias.
  
  
  RESULTS
  Among the 552,569 patients discharged from the emergency department with a primary diagnosis of hypertension, 93 (.017%) were diagnosed with intracerebral hemorrhage during days 8-38 after discharge compared to 70 (.013%) during days 373-403 (odds ratio 1.33, 95% confidence interval .96-1.84). The odds of intracerebral hemorrhage were increased in certain subgroups of patients (≥60 years of age and those with secondary discharge diagnoses besides hypertension), but absolute risks were low in all subgroups.
  
  
  CONCLUSIONS
  Patients with emergency department discharges for hypertension do not face a substantially increased short-term risk of intracerebral hemorrhage after discharge.
authors.affiliation: Department of Neurology, Weill Cornell Medical College, New York, New York; Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York. Electronic address: ban9003@med.cornell.edu.
authors.forename: Babak B
authors.initials: BB
authors.lastname: Navi
authors.affiliation: Department of Neurology, Weill Cornell Medical College, New York, New York.
authors.forename: Neal S
authors.initials: NS
authors.lastname: Parikh
authors.affiliation: Department of Neurology, Weill Cornell Medical College, New York, New York.
authors.forename: Michael P
authors.initials: MP
authors.lastname: Lerario
authors.affiliation: Department of Neurology, Weill Cornell Medical College, New York, New York.
authors.forename: Alexander E
authors.initials: AE
authors.lastname: Merkler
authors.affiliation: Department of Emergency Medicine, Weill Cornell Medical College, New York, New York.
authors.forename: Richard I
authors.initials: RI
authors.lastname: Lappin
authors.affiliation: Department of Emergency Medicine, University of California, San Francisco, California.
authors.forename: Jahan
authors.initials: J
authors.lastname: Fahimi
authors.affiliation: Department of Neurology, Weill Cornell Medical College, New York, New York; Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York.
authors.forename: Costantino
authors.initials: C
authors.lastname: Iadecola
authors.affiliation: Department of Neurology, Weill Cornell Medical College, New York, New York; Feil Family Brain and Mind Research Institute, Weill Cornell Medical College, New York, New York.
authors.forename: Hooman
authors.initials: H
authors.lastname: Kamel
mesh_terms: D000067575:Administrative Claims, Healthcare; D000328:Adult; D000368:Aged; D018592:Cross-Over Studies; D016208:Databases, Factual; D004636:Emergency Service, Hospital; D005260:Female; D006801:Humans; D006973:Hypertension / Q000150:complications* / Q000175:diagnosis; D020299:Intracranial Hemorrhage, Hypertensive / Q000000981:diagnostic imaging / Q000209:etiology*; D008297:Male; D008875:Middle Aged; D016017:Odds Ratio; D010351:Patient Discharge; D011379:Prognosis; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors; D014481:United States
keywords: Hypertension; emergency department; intracerebral hemorrhage; risk factors; stroke