New Anticoagulants Not Linked To Excess Bleeding Rates

–Observational study compares new anticoagulants to warfarin in VTE population.

In clinical trials the new oral anticoagulants (NOACs) have been shown to have similar efficacy and safety compared to warfarin, but questions have been raised about whether the results are similar in real world settings. Now a new observational study lends some measure of reassurance that the new drugs are not associated with increased bleeding risks.

Researchers in Canada performed a retrospective, matched cohort study analyzing data from 59,525 venous thromboembolism (VTE) patients in 6 separate healthcare systems in the US and Canada. They compared 12,489 patients taking one of the NOACs with 47,036 warfarin users. The vast majority (94.9% of the NOAC group were taking rivaroxaban.

Overall 1.7% of the study subjects died and 3.3% had a major bleed. At 30 days the bleeding rate was 2.9% for warfarin and ranged between 0.2% and 2.9% for the NOACs. At 60 days the bleeding rates were 4.3% for warfarin and ranged between 0.4% and 4.3% for the NOACs.

The hazard ratio for major bleeding for NOAC use compared with warfarin use was 0.92 (CI 0.82-1.03). There was also no significant difference in mortality (HR 0.99) and there were no significant differences based on age, sex, or whether or not patients had chronic kidney disease.

NOACs, the writers conclude in their BMJ paper, “show no increased risk of gastrointestinal bleeding associated” with NOAC use.” The findings suggest that NOACs “may be considered as a treatment option for patients with venous thromboembolism who are candidates for anticoagulation,” the authors concluded. But, they cautioned, since it is an observational study they were unable, of course, to fully eliminate the possibility of residual confounding.


  1. Hi, it seems like the prescribing trend in the study sites was rather biased :).

    What bothers me more is the fact that there was no difference in the all cause mortality. Despite the study’s was intent to describe the safety of the NOACs/rivaroxaban it also gives us some insights in the efficacy.

    In my opinion is tells us that there is no difference in efficacy and safety between NOACs/rivaroxaban and warfarin.

    Correct me if I am wrong since I don’t know which endpoints were used to assess the efficacy of the NOACs/rivaroxaban.

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