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Association between warfarin and COVID-19-related outcomes compared with direct oral anticoagulants: population-based

, Angel Y S Wong1, Laurie A Tomlinson2

  • 1Faculty of Epidemiology and Population Health, London School of Hygiene and Tropical Medicine, London, UK. Angel.Wong@lshtm.ac.uk.

Journal of Hematology & Oncology
|October 20, 2021
PubMed

Insights

Warfarin use was associated with a lower risk of COVID-19 outcomes compared to direct oral anticoagulants (DOACs). This large study found no evidence of harmful effects from warfarin in patients with severe COVID-19.

Area of Science:

  • Cardiology
  • Infectious Diseases
  • Pharmacology

Background:

  • Thromboembolism is a known complication of severe COVID-19.
  • Warfarin, a vitamin K antagonist anticoagulant, may have altered efficacy due to low vitamin K levels in severe COVID-19 patients.
  • Limited clinical evidence exists regarding warfarin's impact on COVID-19-related thromboembolism.

Purpose of the Study:

  • To investigate the association between warfarin use and COVID-19 outcomes compared to direct oral anticoagulants (DOACs).
  • To evaluate the safety and efficacy of warfarin in patients with non-valvular atrial fibrillation during the COVID-19 pandemic.

Main Methods:

  • Population-based cohort study using the OpenSAFELY platform in England.
  • Linked primary care, SARS-CoV-2 testing, hospital admission, and death record data.
  • Cox regression analysis comparing warfarin to DOACs for COVID-19-related outcomes and negative control outcomes.

Main Results:

  • Included 92,339 warfarin users and 280,407 DOAC users.
  • Warfarin was associated with a lower risk of SARS-CoV-2 testing positive (HR 0.73), COVID-19 hospital admission (HR 0.75), and COVID-19 deaths (HR 0.74) compared to DOACs.
  • Lower risk observed for negative control outcomes (testing for SARS-CoV-2 and non-COVID-19 deaths) with warfarin.

Conclusions:

  • This study found no evidence of harmful effects associated with warfarin use in severe COVID-19.
  • Warfarin demonstrated a comparable or potentially lower risk profile for COVID-19-related outcomes compared to DOACs.
Abstract

Keywords:
COVID-19Direct oral anticoagulantsWarfarin

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