Comparative Effectiveness of Direct Oral Anticoagulants and Warfarin on Venous Thromboembolism in Cancer Patients

Introduction: Venous thromboembolism (VTE) is a leading cause of mortality in cancer patients, and a substantial number of patients are being treated with oral anticoagulants. We aim to assess the comparative effectiveness of direct oral anticoagulants (DOACs) compared to warfarin for VTE treatment in cancer patients. Methods: In this retrospective cohort study, we included 2,367 cancer patients who are new users of oral anticoagulants (OACs) for VTE treatment from 2009 to 2021 in NHS Scotland. Patients were grouped by OAC type, DOACs or warfarin. To adjust for confounding, inverse probability treatment weighting was applied. Outcomes included mortality, VTE recurrence, and major bleeding. We calculated Hazard Ratio (HR) using Cox regression and sub-distribution HR (sHR) using a competing risk framework (Fine and Gray method) for VTE recurrence and major bleeding. Subgroup analyses were conducted for individual DOACs. Results: Patients on DOACs had lower risks of VTE recurrence (sHR 0.73 95% CI 0.59–0.90) and major bleeding (sHR 0.68, 95% CI 0.53–0.88) compared to patients on warfarin. Patients on rivaroxaban (HR 1.21, 95% CI 1.04–1.39) and edoxaban (HR 1.59, 95% CI 1.15–2.22) had a significantly higher risk of mortality, while a comparable risk of mortality was observed (HR 0.91, 95% CI 0.76–1.08) for patients on apixaban compared to patients on warfarin. Conclusion: This study provides insight into the effectiveness of DOACs compared to warfarin for VTE in cancer patients. Patients on DOACs had lower risks of VTE recurrence and major bleeding. We suggest healthcare professionals consider the potential benefits of individual DOACs when making treatment decisions.