COVID-19-related Outcomes in Warfarin and DOAC Users

Pavankumar Kamat


November 07, 2021


  • In patients with non-valvular atrial fibrillation (AF), the use of warfarin was associated with a lower risk of developing SARS-CoV-2 infection and hospital admission or death from COVID-19 compared with the use of direct oral anticoagulants (DOACs).

Why this matters

  • Findings provide reassurance about the safety of warfarin use in patients with indications for anticoagulation during the COVID-19 pandemic.

Study design

  • A population-based cohort study included 92,339 warfarin users and 280,407 DOAC users from England.

  • COVID-19-related outcomes (testing positive for SARS-CoV-2, COVID-19-related hospital admission and COVID-19-related deaths) were compared between warfarin and DOAC users.

  • Funding: None.

Key results

  • Warfarin vs DOAC users had a lower risk of (adjusted HR [aHR]; 95% CI):

    • testing positive for SARS-CoV-2 (0.73; 0.68-0.79);

    • COVID-19-related hospital admission (0.75; 0.68-0.83); and

    • COVID-19-related deaths (0.74; 0.66-0.83).

  • For negative control outcomes, warfarin vs DOAC use was linked to a lower risk of:

    • being tested for SARS-CoV-2 (0.80; 0.79-0.81); and

    • non-COVID-19-related deaths (0.79; 0.76-0.83).


  • Risk of residual confounding.

  • The study did not include data on any anticoagulant use during hospitalisation.

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OpenSAFELY Collaborative, Wong AYS, Tomlinson LA, Brown JP, Elson W, Walker AJ, Schultze A, Morton CE, Evans D, Inglesby P, MacKenna B, Bhaskaran K, Rentsch CT, Powell E, Williamson E, Croker R, Bacon S, Hulme W, Bates C, Curtis HJ, Mehrkar A, Cockburn J, McDonald HI, Mathur R, Wing K, Forbes H, Eggo RM, Evans SJW, Smeeth L, Goldacre B, Douglas IJ. Association between warfarin and COVID-19-related outcomes compared with direct oral anticoagulants: population-based cohort study. J Hematol Oncol. 2021;14(1):172. doi: 10.1186/s13045-021-01185-0. PMID: 34666811  View full text

This clinical summary originally appeared on Univadis, part of the Medscape Professional Network.


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