Respiratory Tract Infection and Bleeding Risk in Anticoagulant Users

Pavankumar Kamat


January 10, 2022


  • The risk of major bleeding and clinically relevant non-major bleeding (CRNMB) was more than 2-fold higher among oral anticoagulant users during the 0-14 days following a community-acquired respiratory tract infection (RTI) for which no antibiotics were prescribed.

Why this matters

  • Findings may have potential implications for how patients and clinicians manage oral anticoagulant use during an acute intercurrent illness.

Study design

  • A self-controlled case series included 1208 patients who were prescribed warfarin or a direct oral anticoagulant and those with an untreated community-acquired RTI, identified from the UK Clinical Practice Research Datalink (CPRD) GOLD database (2010-2019).

  • Main outcomes: incidence of major bleeding and CRNMB during the 0-14 days following an untreated RTI compared with unexposed time periods.

  • Funding: Health and Care Research Wales.

Key results

  • Overall, 395 major bleeds were reported, of which 292 were reported during 287,579 days of observation of the unexposed period and 41 were reported during 6710 days of observation of the 0-14 day risk window.

  • Overall, 1272 CRNMBs were reported, of which 1003 were reported during 827,042 days of observation of the unexposed period and 81 were reported during 23,166 days of observation of the 0-14 day risk window.

  • After adjustment for confounders, the relative incidence of major bleeding (incidence rate ratio [IRR], 2.68; 95% CI 1.83 to 3.93) and CRNMB (IRR, 2.32; 95% CI 1.82 to 2.94) was higher among oral anticoagulant users during the 0 to 14 days following an untreated RTI.


  • Participants included only those that had consulted a healthcare professional for their RTI.

Ahmed H, Whitaker H, Farewell D, Hippisley-Cox J, Noble S. Respiratory tract infection and risk of bleeding in oral anticoagulant users: self-controlled case series. BMJ. 2021;375:e068037. doi: 10.1136/bmj-2021-068037. PMID: 34933893 View Full Text.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.