Real-world data reassures DOAC safety in VTE
Treatment with direct-acting oral anticoagulants (DOACs) was not associated with increased risks of major bleeding or deaths from any cause within 90 days of therapy initiation, when compared with warfarin in adults with newly diagnosed venous thromboembolism (VTE), according to a large real-world study.
While DOACs have been shown to be noninferior to warfarin in treating VTE in randomized controlled trials, the researchers noted that “clinical trials include a highly selected patient group … bleeding rates are underestimated in randomized trials, as patients with a history of bleeding are usually excluded … [which] often [do] not reflect those observed in routine clinical practice.” Therefore, real-world evidence is needed to inform clinical practice.
The multicentre retrospective population-based study included 59,525 adults (mean age 64.3 years, 53.6 percent females) who had been newly diagnosed with VTE and prescribed a DOAC or warfarin during the 30 days following their diagnosis, based on healthcare data from hospitals and emergency departments. Of the total participants, 12,489 were DOAC users (of which 94.9 percent used rivaroxaban) who were propensity-score matched to 47,036 warfarin users. [BMJ 2017;359:j4323]
After a mean 85.2 days follow-up, there was no increase in major bleeding risk with DOACs vs warfarin (pooled hazard ratio [HR], 0.92, 95 percent confidence interval [CI], 0.82–1.03), with the overall trend favouring DOAC use.
Risk of all-cause mortality was also similar between the two groups (HR, 0.99, 95 percent CI, 0.84–1.16).
“[G]iven the absence of an increased bleeding risk and the advantages associated with its use particularly around frequency of monitoring and dosing, our results suggest that DOACs may be considered as a treatment option for patients with VTE who are candidates for anticoagulation,” said the researchers.
Sensitivity analyses including a longer follow-up of 180 days showed that the results remained unchanged.
The findings were also consistent across age, sex, or chronic kidney disease status.
Nonetheless, a previous systematic review has shown that the extent of reduction in major bleeding with DOAC vs warfarin was dependent on the percentage renal excretion of the drug. [Thromb Haemost 2014;12:337-343] While DOACs with renal excretion of <50 percent (eg, rivaroxaban and apixaban) showed reduced major bleeding compared with warfarin, use of agents with renal excretion above 50 percent such as dabigatran was not associated with reduced major bleeds relative to warfarin.
As the majority of DOAC users in the study took rivaroxaban, the researchers cautioned against extrapolating their findings to other DOAC agents, calling for future studies on the safety of other DOACs in VTE. They also added that DOAC safety in the longer term (beyond 180 days as studied) for VTE treatment remained uncertain.