Risk of bleeding amongst warfarin and direct oral anticoagulant users prescribed immediate antibiotics for respiratory tract infection: cohort study

Ahmed, Haroon ORCID: https://orcid.org/0000-0002-0634-8548, Reeve, Nicola, Farewell, Daniel ORCID: https://orcid.org/0000-0002-8871-1653, Hamilton, Fergus, Ponsford, Mark, Hippisley‐Cox, Julia and Noble, Simon ORCID: https://orcid.org/0000-0001-5425-2383 2024. Risk of bleeding amongst warfarin and direct oral anticoagulant users prescribed immediate antibiotics for respiratory tract infection: cohort study. Pharmacoepidemiology & Drug Safety 33 (5) , e5794. 10.1002/pds.5794

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Abstract

Purpose: Incidence of bleeding amongst warfarin and direct oral anticoagulant (DOAC) users is greater following a respiratory tract infection (RTI). It is unclear whether immediate antibiotics modify this association. We estimated the risk of bleeding amongst warfarin and DOAC users with RTI by antibiotic treatment. Methods: This retrospective cohort study used data from the Clinical Practice Research Datalink (CPRD) GOLD for adults in England prescribed warfarin or a DOAC, who sought primary care for an RTI between 1st January 2011 and 31st December 2019. Outcomes were major bleeding (hospital admission for intracranial or gastrointestinal bleeding), and non‐major bleeding (hospital admission or General Practice consult for epistaxis, haemoptysis, or haematuria). Cox models derived hazard ratios (HRs) and 95% confidence intervals (CIs) for each outcome, adjusting for confounders using inverse probability of treatment weighting. Results: Of 14 817 warfarin and DOAC users consulting for an RTI, 8768 (59%) were prescribed immediate antibiotics and 6049 (41%) were not. Approximately 49% were female, and median age was 76 years. Antibiotics were associated with reduced risk of major bleeding (adjusted HR 0.38, 95% CI 0.25 to 0.58). This was consistent across several sensitivity analyses. Antibiotics were also associated with a reduced risk of non‐major bleeding (adjusted HR 0.78, 95% CI 0.61 to 0.99). Conclusions: Immediate antibiotics were associated with reduced risk of bleeding amongst warfarin and DOAC users with an RTI. Further work is needed to understand mechanisms and confirm whether a lower threshold for antibiotic use for RTI in this population may be beneficial.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Medicine
Additional Information:	License information from Publisher: LICENSE 1: URL: http://creativecommons.org/licenses/by/4.0/
Publisher:	Wiley
ISSN:	1053-8569
Date of First Compliant Deposit:	30 April 2024
Date of Acceptance:	1 April 2024
Last Modified:	30 Apr 2024 08:30
URI:	https://orca.cardiff.ac.uk/id/eprint/168497

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