INTRODUCTION: Venous thromboembolism (VTE) is a fatal comorbidity prevalent in cancer patients. Low-molecular weight heparins (LMWHs) have been the preferred treatment for cancer associated thrombosis (CAT). Direct-oral anticoagulants (DOACs) are a relatively newer drug class used for treating CAT. Treatment guidelines provide inconsistent recommendations. This study aimed to study the prevalence and predictors associated with utilization of these anticoagulation strategies.
METHODS: This retrospective cohort study used SEER Medicare data from years 2011-2019. Patients with lung, pancreatic, breast, colorectal, prostate, and/or stomach cancer, diagnosed with a VTE and a prescription of a LMWH or DOAC were included. Patients had to be over the age of 65 during VTE diagnosis and continuously enrolled in Medicare parts A, B & D for one year before the VTE diagnosis. Multivariable logistic regression was employed to identify significant factors associated with the use of DOACs versus LMWHs.
RESULTS: The cohort included 4892 LMWH and 5080 DOAC treated patients. Patients with more advanced cancer (OR=0.54, 95% CI=0.41-0.70) were significantly less likely to receive a DOAC as compared to patients in the initial stages. Certain cancer types including breast (OR=1.93, 95% CI=1.65-2.25), colorectal (OR=1.50, 95% CI=1.18-1.90) and prostate (OR=2.12, 95% CI=1.77-2.52) were more likely than lung cancer patients to be prescribed DOACs. Stomach (OR=0.83, 95% CI=0.64-1.07) and pancreatic (OR=0.78, 95%CI=0.66-0.91) cancer patients were less likely to be on DOACs as compared to lung cancer patients. Patients were significantly more likely to be prescribed a DOAC in 2019 (OR=106.39, 95% CI= 42.19-268.28) and the more recent years as compared to 2011. Patients on active cancer treatment were less likely to be on a DOAC (OR=0.74, 95% CI=0.67-0.81).
CONCLUSION: Several sociodemographic and clinical characteristics were associated with the use of DOACs, with year of VTE diagnosis being the strongest predictor. Even without a consistent clinical guideline physicians have been prescribing DOACs to patients.
