Association between oral anticoagulants and COVID-19-related outcomes

This paper investigates the association between OACs and COVID-19 outcomes in those with atrial fibrillation and a CHA2DS2-VASc score of 2.

British Journal of General Practice, 2022

Paper information

Association between oral anticoagulants and COVID-19-related outcomes: a population-based cohort study. Angel YS Wong, Laurie Tomlinson, Jeremy P Brown, William Elson, Alex J Walker, Anna Schultze, Caroline E Morton, David Evans, Peter Inglesby, Brian MacKenna, Krishnan Bhaskaran, Christopher T Rentsch, Emma Powell, Elizabeth Williamson, Richard Croker, Seb Bacon, William Hulme, Chris Bates, Helen J Curtis, Amir Mehrkar, Jonathan Cockburn, Helen I McDonald, Rohini Mathur, Kevin Wing, Harriet Forbes, Rosalind M Eggo, Stephen JW Evans, Liam Smeeth, Ben Goldacre, Ian J Douglas, (The OpenSAFELY Collaborative). British Journal of General Practice 2022; 72 (720): e456-e463. DOI: 10.3399/BJGP.2021.0689



Early evidence has shown that anticoagulant reduces the risk of thrombotic events in those infected with COVID-19. However, evidence of the role of routinely prescribed oral anticoagulants (OACs) in COVID-19 outcomes is limited.


On behalf of NHS England, a population-based cohort study was conducted. The study used primary care data and pseudonymously-linked SARS-CoV-2 antigen testing data, hospital admissions, and death records from England. Cox regression was used to estimate hazard ratios (HRs) for COVID-19 outcomes comparing people with current OAC use versus non-use, accounting for age, sex, comorbidities, other medications, deprivation, and general practice.


Of 71 103 people with atrial fibrillation and a CHA2DS2-VASc score of 2, there were 52 832 current OAC users and 18 271 non-users. No difference in risk of being tested for SARS-CoV-2 was associated with current use (adjusted HR [aHR] 0.99, 95% confidence interval [CI] = 0.95 to 1.04) versus non-use. A lower risk of testing positive for SARS-CoV-2 (aHR 0.77, 95% CI = 0.63 to 0.95) and a marginally lower risk of COVID-19-related death (aHR, 0.74, 95% CI = 0.53 to 1.04) were associated with current use versus non-use.


Among those at low baseline stroke risk, people receiving OACs had a lower risk of testing positive for SARS-CoV-2 and severe COVID-19 outcomes than non-users; this might be explained by a causal effect of OACs in preventing severe COVID-19 outcomes or unmeasured confounding, including more cautious behaviours leading to reduced infection risk.