Comparative Effectiveness and Safety of Direct-acting Oral Anticoagulants and Warfarin in Patients with Venous Thromboembolism and Active Cancer: An Observational Analysis

Purpose

There is limited evidence to support the use of direct-acting oral anticoagulants
(DOACs) in patients with venous thromboembolism (VTE) and active cancer. This study
aimed to assess the effectiveness of DOACs versus warfarin for the prevention of recurrent
VTE and major bleeding events in patients with VTE and active cancer.

Methods

We identified patients with incident VTE and active cancer who newly initiated treatment
with DOACs or warfarin from Truven Health MarketScan Commercial Claims and Medicare
supplemental databases. Patients were followed up from treatment initiation (index
date) until the occurrence of >7-day gap in treatment, the start of the study comparator,
an outcome of interest (recurrent VTE or major bleeding), inpatient death, disenrollment,
or end of the study period, whichever occurred first. We controlled for confounders
via propensity score matching and estimated the hazard ratios (HRs) using Cox proportional
hazards regression models.

Findings

A total of 9952 patients were included in the matched cohort (4976 DOACs users and
4976 warfarin users). Patient characteristics were well balanced after matching. We
observed a lower incidence of recurrent VTE (3 vs 5 per 100 person-years) and major
bleeding events (2 vs 3 per 100 person-years) in the DOAC group compared to warfarin
group, respectively. In Cox regression models, use of DOACs (vs warfarin) was associated
with a lower risk of recurrent VTE (hazard ratio (HR), 0.59; 95% CI, 0.42–0.82) and
major bleeding events (HR, 0.64; 95% CI, 0.44–0.94).

Implications

On the basis of our findings, among patients with VTE and active cancer, DOACs offer
superior effectiveness with a lower risk of bleeding when compared with warfarin for
the secondary prevention of VTE.

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