Methodology: 3/5
Usefulness: 3/5

Grewal K, et al. CMAJ. 2021 Oct 12;193(40):E1561-E1567. 

Question and Methods: Retrospective cohort study evaluating risk of ICH post head injury in ED patients >65 years on warfarin or DOAC or no anticoagulant.
Findings: Patients on warfarin had an increased risk of ICH compared with matched patients on DOACs (RR 1.43, 95% CI 1.20–1.69) and no anticoagulation (RR 1.36, 95% CI 1.15–1.61). No difference in ICH between patients not on anticoagulation and DOACS.
Limitations: No laboratory data to evaluate coagulation markers

Interpretation: Patients on warfarin with head injury had higher relative risk of ICH than matched patients on DOAC and no anticoagulation.

By: Dr. Graham Wilson

Supervision: Dr. Jeff Perry



  • Graham Wilson

    Dr. Graham Wilson is a FRPCP Emergency Medicine resident at the University of Ottawa with a passion for the outdoors, and sustainable environmental change.

  • Jeff Perry

    Dr. Perry is an Emergency Physician and full Professor in the department of Epidemiology and Community Medicine. He has a special research interest in subarachnoid hemorrhage, TIA and stroke.

  • Hans Rosenberg

    Dr. Rosenberg is an emergency physician at the Ottawa Hospital, associate professor at the University of Ottawa, and Director of the Digital Scholarship and Knowledge Dissemination Program.