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CC BY 4.0 · TH Open 2024; 08(01): e19-e30
DOI: 10.1055/a-2202-4296
Original Article

Anticoagulation-Associated Bleeding in Patients Screened for Atrial Fibrillation versus Usual Care—A Post Hoc Analysis from the LOOP Study

Authors

  • Emilie Katrine Kongebro 

    1   Department of Cardiology, Copenhagen University Hospital—Rigshospitalet, Copenhagen, Denmark

  • Søren Zöga Diederichsen

    1   Department of Cardiology, Copenhagen University Hospital—Rigshospitalet, Copenhagen, Denmark

  • Lucas Yixi Xing

    1   Department of Cardiology, Copenhagen University Hospital—Rigshospitalet, Copenhagen, Denmark

  • Ketil Jørgen Haugan

    2   Department of Cardiology, Zealand University Hospital Roskilde, Roskilde, Denmark

  • Claus Graff

    3   Department of Health Science and Technology, Aalborg University, Aalborg, Denmark

  • Søren Højberg

    4   Department of Cardiology, Bispebjerg Hospital, Copenhagen University Hospital, Copenhagen, Denmark

  • Morten S. Olesen

    1   Department of Cardiology, Copenhagen University Hospital—Rigshospitalet, Copenhagen, Denmark
    5   Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark

  • Derk Krieger

    6   Mohammed Bin Rashid University of Medicine and Health Sciences, Dubai Healthcare City, Dubai, United Arab Emirates
    7   Department of Neurology, Mediclinic Parkview Hospital, Al Barsha South, Dubai, United Arab Emirates

  • Axel Brandes

    8   Department of Cardiology, Odense University Hospital, Odense, Denmark
    9   Department of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Odense C, Denmark
    10   Department of Cardiology, University Hospital of Southern Denmark—Esbjerg, Esbjerg, Denmark

  • Lars Køber

    1   Department of Cardiology, Copenhagen University Hospital—Rigshospitalet, Copenhagen, Denmark
    11   Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark

  • Jesper Hastrup Svendsen

    1   Department of Cardiology, Copenhagen University Hospital—Rigshospitalet, Copenhagen, Denmark
    11   Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark

Funding The LOOP study was supported by The Innovation Fund Denmark (12-135225), The Research Foundation for the Capital Region of Denmark (no grant number), The Danish Heart Foundation (11-04-R83-A3363-22625), Aalborg University Talent Management Programme (no grant number), Arvid Nilssons Fond (no grant number), Skibsreder Per Henriksen, R. og Hustrus Fond (no grant number), Medtronic (no grant number), and the AFFECT-EU consortium which has received funding from the European Union's Horizon 2020 research and innovation program under grant agreement No 847770.
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Abstract

Background Atrial fibrillation (AF) prevalence is rising; however, data on the bleeding risks associated with the detection of subclinical AF are needed.

Objective Our objective was to determine the bleeding increment associated with implantable loop recorder (ILR) screening for subclinical AF and subsequent anticoagulation initiation compared with usual care.

Methods This post hoc study utilized LOOP trial data from 6,004 elderly patients with stroke risks randomized to either ILR (n = 1,503) or usual care (n = 4,503). The mean follow-up time was 64.5 months, and none were lost to follow-up. The primary exposure was the initiation of oral anticoagulation, and the main outcome was the risk of major bleeding events following initiation of oral anticoagulants (OACs), determined by time-dependent cox regression. Second, we investigated antithrombotic prescription patterns and major bleeding events after antiplatelet treatment and in subgroups.

Results OAC was initiated in 1,019 participants with a mean age (years) of 78.8 (± 4.67) in control versus 77.0 (± 4.84) in ILR, p < 0.0001. Altogether did 202 participants end or pause OAC treatment. Among AF patients (n = 910) had 40 (28%) completely ended OAC and 105 (72%) temporarily paused OAC during follow-up. Major bleeding events totaled 221 (3.7%). Forty-seven major bleeding events followed an OAC initiation in 1,019 participants (4.6%); 26 versus 21 events in the control and ILR groups, respectively. The hazard ratio (HR) for major bleeding after OAC initiation compared with before initiation was 2.08 (1.50–2.90) p < 0.0001 overall, 2.81 (1.82–4.34) p < 0.0001 for control and 1.32 (0.78–2.23) p = 0.31 for the ILR group (p = 0.07 for interaction). Antiplatelet treatment resulted in an overall adjusted HR of 1.3 (0.96–1.75) p = 0.09. For OAC users aged ≥75 years in the ILR group, the rate of major bleeding was 1.73 (0.92–2.96) compared with 0.84 (0.36–1.66) for an age <75 years, and the rate of the corresponding control subgroup aged ≥75 years was 2.20 (1.23–3.63) compared with 1.64 (0.82–2.93) for an age <75 years.

Conclusion The individual risk of major bleeding increased twofold after initiation of oral anticoagulation for all patients in this study. However, the patients screened for subclinical AF did not have a higher bleeding risk after initiation of anticoagulation compared with those in usual care.

Trial Registration: The LOOP study is registered at ClinicalTrials.gov, identifier: NCT020364 50

Keywords

major bleeding - subclinical atrial fibrillation - implantable loop recorder screening - oral anticoagulation

Supplementary Material



Publication History

Received: 26 June 2023

Accepted: 14 October 2023

Accepted Manuscript online:
01 November 2023

Article published online:
08 January 2024

© 2024. The Author(s). This is an open access article published by Thieme under the terms of the Creative Commons Attribution License, permitting unrestricted use, distribution, and reproduction so long as the original work is properly cited. (https://creativecommons.org/licenses/by/4.0/)

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