Prevalence of Intracranial Injury in Adult Patients With Blunt Head Trauma With and Without Anticoagulant or Antiplatelet Use

Ann Emerg Med. 2020 Mar;75(3):354-364. doi: 10.1016/j.annemergmed.2019.10.004. Epub 2020 Jan 17.


Study objective: We determine the prevalence of significant intracranial injury among adults with blunt head trauma who are receiving preinjury anticoagulant or antiplatelet medications.

Methods: This was a multicenter, prospective, observational study conducted from December 2007 to December 2015. Patients were enrolled in 3 emergency departments (EDs) in the United States. Adults with blunt head trauma who underwent neuroimaging in the ED were included. Use of preinjury aspirin, clopidogrel, and warfarin was recorded. Data on direct oral anticoagulants were not specifically recorded. The primary outcome was prevalence of significant intracranial injury on neuroimaging. The secondary outcome was receipt of neurosurgical intervention.

Results: Among 9,070 patients enrolled in this study, the median age was 53.8 years (interquartile range 34.7 to 74.3 years) and 60.7% were men. A total of 1,323 patients (14.6%) were receiving antiplatelet medications or warfarin, including 635 receiving aspirin alone, 109 clopidogrel alone, and 406 warfarin alone. Compared with that of patients without any coagulopathy, the relative risk of significant intracranial injury was 1.29 (95% confidence interval [CI] 0.88 to 1.87) for patients receiving aspirin alone, 0.75 (95% CI 0.24 to 2.30) for those receiving clopidogrel alone, and 1.88 (95% CI 1.28 to 2.75) for those receiving warfarin alone. The relative risk of significant intracranial injury was 2.88 (95% CI 1.53 to 5.42) for patients receiving aspirin and clopidogrel in combination.

Conclusion: Patients receiving preinjury warfarin or a combination of aspirin and clopidogrel were at increased risk for significant intracranial injury, but not those receiving aspirin alone. Clinicians should have a low threshold for neuroimaging when evaluating patients receiving warfarin or a combination of aspirin and clopidogrel.

Publication types

  • Multicenter Study
  • Observational Study
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Anticoagulants / adverse effects*
  • Aspirin / adverse effects
  • Brain Injuries / epidemiology*
  • Brain Injuries / etiology
  • Clopidogrel / adverse effects
  • Female
  • Head Injuries, Closed / complications*
  • Humans
  • Male
  • Middle Aged
  • Platelet Aggregation Inhibitors / adverse effects*
  • Prevalence
  • Prospective Studies
  • Risk Factors
  • Warfarin / adverse effects


  • Anticoagulants
  • Platelet Aggregation Inhibitors
  • Warfarin
  • Clopidogrel
  • Aspirin