INTRODUCTION: Cancer patients are at an increased risk of thrombosis and bleeding. Low-molecular weight heparins (LMWHs) have been the therapy of choice for cancer associated thrombosis (CAT). Direct-oral anticoagulants (DOACs) are a relatively newer class of drugs used for the treatment of CAT. There is limited real-world data on the safety and effectiveness of DOACs in cancer patients. This study conducted a comparative effectiveness and safety analysis of these anticoagulants.
METHODS: This retrospective cohort study used SEER Medicare data from the years 2011-2019. Cancer patients who were diagnosed with VTE and received either a LMWH or a DOAC were included in the cohort. Patients had to be age >=66 at the time of VTE diagnosis and continuously enrolled in Medicare parts A, B & D. An intention to treat approach was employed in which patients were categorized into either of the anticoagulant group depending on the first anticoagulant a patient was started on post CAT diagnosis. Patients were followed for 12 months and time to recurrent VTE and bleeding events between these two cohorts were compared using weighted Cox Proportional Hazards Regression and Kaplan Meier Curves.
RESULTS: The study cohort included 4892 LMWH and 5080 DOAC treated patients. Lower rates of recurrent VTE were found in DOAC patients (HR=0.66, 95% CI=0.54-0.81) in the intention to treat analysis as well as in the different sensitivity analyses. A significant reduction in the risk of major bleeding (HR=0.84, 95% CI=0.73-0.96) was found in the DOAC cohort in the intention to treat analysis, however when patients were censored at discontinuation/switch the two groups had similar bleeding rates.
CONCLUSION: This study suggests that cancer patients treated with DOACs had significantly lower rates of recurrent VTE, however similar bleeding rates. More research needs to be done on a larger population to assess its effectiveness in a larger population.
