In order to bring you the best possible user experience, this site uses Javascript. If you are seeing this message, it is likely that the Javascript option in your browser is disabled. For optimal viewing of this site, please ensure that Javascript is enabled for your browser.
Did you know that your browser is out of date? To get the best experience using our website we recommend that you upgrade to a newer version. Learn more.

We use cookies to optimise the design of this website and make continuous improvement. By continuing your visit, you consent to the use of cookies. Learn more

RE-LY: Concomitant use of antiplatelet therapy with dabigatran or warfarin in the randomized evaluation of long-term anticoagulation therapy (RE-LY®) trial

Atrial Fibrillation

Presenter | see Discussant report

Antonio Miguel Dans (Philippines)

List of Authors:
Dans AL, Connolly S, Brückmann M, Ezekowitz M, Wallentin L, Yang S, Reilly P, Yusuf S


Background and Objectives: The RELY trial compared 2 doses of Dabigatran Etexilate (DE) to warfarin in 18,113 patients with atrial fibrillation (AF). Results showed that the 150 mg bid dose (DE 150) was superior, and the 110 mg bid dose (DE 110) non-inferior to warfarin in preventing stroke and systemic embolism (SSE). Many patients with AF suffer from conditions that require concomitant antiplatelet drugs that may interact with DE. It is therefore important to assess the efficacy and safety of DE vs warfarin in those receiving or not receiving other antiplatelets.

Methods: In this post-hoc analysis, we compared the efficacy and safety of DE 110 and DE 150 to warfarin, in subgroups of patients with and without concomitant antiplatelet use during the study. The main efficacy outcome was SSE and the main safety outcome was major bleeding (MB). We also compared major bleeding rates in patients with and without concomitant antiplatelets, adjusting for known risk factors for bleeding.

Results: A total of 6952 patients (38.4%) received concomitant ASA or clopidogrel during the study. Use of other antiplatelets was negligible. As in the main study results, DE 110 mg bid was non-inferior to warfarin in terms of the primary endpoint of SSE. This was true whether patients were on concomitant antiplatelets (HR=0.93, 95%CI:0.70-1.25) or not (HR=0.87, 95%CI:0.66-1.15; p for interaction= 0.7377). In terms of the main safety outcome of major bleeding, DE 110 was superior to warfarin. This effect was also unaffected by concomitant antiplatelet use (HR=0.82; 95%CI: 0.67-1.00 for patients on antiplatelets; HR=0.79; 95%CI: 0.64-0.96 for patients without antiplatelets; p for interaction=0.7945).

The higher dose of dabigatran (DE 150) was superior to warfarin in terms of the primary outcome of SSE, particularly among patients who were not on antiplatelets (HR=0.52; 95%CI:0.38-0.72). This effect seemed to diminish when concomitant antiplatelets were given (HR=0.80; 95%CI:0.59-1.08), but the difference was not statistically significant (p for interaction = 0.0578), especially after correction for multiplicity of analyses. With respect to MB, DE 150 was similar to warfarin regardless of concomitant antiplatelet use (HR=0.93, 95%CI:0.76-1.12 for patients on antiplatelets; HR=0.94, 95%CI:0.78-1.15 for patients without antiplatelets; p for interaction=0.8746).

Overall, the rates of major bleeding increased when antiplatelets were given concomitantly with anticoagulants (HR=1.60, 95% CI=1.41-1.81 after adjustment for age, gender, warfarin experience, systolic BP, coronary artery disease, heart failure, hypertension, diabetes, prior TIA, creatinine clearance and statin use). The relative increase was consistent whether patients were on DE 110, DE 150 or warfarin, but the absolute risks were lowest on DE 110. These results were unaffected by duration of antiplatelet use (<50% or >50% of the trial duration) or number of antiplatelets used (aspirin alone, clopidogrel alone, or the 2 in combination).

Conclusion: Concomitant use of aspirin or clopidogrel increased the relative risks for bleeding in all treatment arms of the RE-LY study. However, the lowest absolute risk for bleeding was noted on DE 110. The relative advantages of DE 110 and DE 150 over warfarin (seen in the main trial results) were unaffected by concomitant antiplatelet use.

Discussant | see Presenter abstract

Freek Verheugt (Netherlands)

Presentation webcast

Presentation slides





  • Large numbers from a very well-conducted trial 
  • Important issue 
  • Reassuring outcome 


  • Retrospective, not prespecified analysis 
  • Relatively small numbers 
  • Antiplatelet therapy observational, not randomized 
  • No data on single vs dual antiplatelet therapy 


  1. In RE-LY triple therapy (OAC, ASA and clopidogrel) increases major bleeding by 60% irrespective the anticoagulant used 
  2. The ischemic AND bleeding benefit of dabigatran over warfarin is maintained with antiplatelet therapy 
  3. The lowest rate of ICH in this study is seen with low dose dabigatran, which is even lower than with warfarin without antiplatelets 
  4. Low dose dabigatran seems a good candidate for patients with AF in the need of antiplatelet therapy (e.g, stenting and/or ACS), but this has to be confirmed in a new randomized trial against warfarin. However, it is unlikely, that such a trial will be done


709009 - 709010


Clinical Trial Update I - Drug treatment

The content of this article reflects the personal opinion of the author/s and is not necessarily the official position of the European Society of Cardiology.