DSEN Abstract
Direct oral anticoagulants in venous thromboembolism

A study conducted by the Canadian Network for Observational Drug Effect Studies (CNODES)

Summary

Compared to warfarin, treatment of newly-diagnosed VTE with a DOAC was not associated with an increased risk of major bleeding or all-cause mortality.

These findings provide evidence for the safety of DOACs in the treatment of VTE in a real-world setting.
Physicians may not need to consider the risk of major bleeding when prescribing a DOAC instead of warfarin.

What is the issue?

Direct oral anticoagulants (DOACs) are used in the treatment of venous thromboembolism (VTE). They offer advantages over the use of warfarin, with no need for regular monitoring and dose adjustment.
Clinical trials have shown that DOACs have a comparable efficacy to warfarin, however their safety in a real-world setting remains uncertain.

What was the aim of the study?

CNODES evaluated the safety (major bleeding and all-cause mortality) of DOAC (dabigatran, apixaban or rivaroxaban) use compared with warfarin use for the treatment of VTE.

How was the study conducted?

CNODES undertook a retrospective, propensity score-matched cohort study using health records from 5 Canadian provinces (Alberta, Manitoba, Ontario, Quebec and Saskatchewan) and the US IBM MarketScan® database.
The study cohort included 59,525 adult patients with a new diagnosis of VTE and a prescription for a DOAC or warfarin within 30 days of the diagnosis.
The outcomes were major bleeding requiring hospital admission or emergency department visit and all-cause mortality within 90 days of treatment initiation.
Hazard ratios (HR) and 95% confidence intervals (CI) were estimated and pooled across sites using meta-analysis.

What did the study find?

Among patients with VTE, treatment with DOACs compared to warfarin was not associated with an increased risk of major bleeding (HR 0.92; 95% CI: 0.82 to 1.03) or all-cause mortality (HR 0.99; 95% CI: 0.84 to 1.16).
Results were consistent for patients with and without chronic kidney disease, across all age groups, and for men and women.
These findings provide reassurance as to the risk of major bleeding and all-cause mortality with DOACs in a real-world setting.