AN ASSOCIATION has been discovered linking lower risk of venous thromboembolism (VTE) recurrence and major bleeds by using direct oral anticoagulants for cancer-associated thrombosis. Researchers observed this alongside a reduction in mortality rates for patients with cancer, finding increased risk for major bleeds and all-cause mortality, as well as VTE recurrence, with low molecular-weight heparin (LMWH) and warfarin in comparison.
This research was of retrospective design, in a field where “patterns of clinical utilisation and comparative effectiveness of anticoagulants for cancer-associated thrombosis remain largely unexplored,” in the words of the study leader, Irbaz Bin Riaz, Mayo Clinic Arizona, USA. Riaz and co-authors aimed to assess patterns of, and factors associated with, anticoagulant use, evaluating comparative effectiveness of contemporary anticoagulants.
The cohort under scrutiny included 5,100 patients with active cancer, and a mean age of 66 years; 52% were female, and 70% White. Patients were grouped according to the anticoagulant prescribed, including direct oral anticoagulants, LMWH, and warfarin. The researchers used odds ratios to present associations between factors of interest and the use of anticoagulants.
Median duration of treatment was 3.2 months for direct oral anticoagulants, 3.1 months for warfarin, and 1.8 months for LWMH, respectively. Results presented an increase in prescription fills for LMWH versus direct oral anticoagulants among patients with lung (odds ratio [OR]: 2.07; 95% confidence interval [CI]: 1.12–3.65), urologic (OR: 1.94; 95% CI: 1.08–3.49), gynaecologic (OR: 4.25; 95% CI: 2.31–7.82), and colorectal (OR: 2.26; 95% CI: 1.2–4.32) cancers. LMWH (hazard ratio [HR]: 1.47; 95% CI: 1.14–1.9) and warfarin (HR: 1.46; 95% CI: 1.13–1.87) were associated with increased risk for VTE recurrence compared with direct oral anticoagulants. LMWH also appeared to be associated with an increased risk of major bleeding (HR: 2.27; 95% CI: 1.62–3.2) and higher all-cause mortality (HR: 1.61; 95% CI: 1.15–2.25) compared with direct oral anticoagulants.
The current study also showed that warfarin may still be considered for patients with contraindications to direct anticoagulants and patients with poor persistence on LMWH. Limitations acknowledged were information bias, use of International Classification Disease (ICD) billing codes to identify patients with VTE, and a lack of radiologic evidence of VTE in the database. Concluding their research, the authors wrote that their results “reinforce the general efficacy and safety of direct oral anticoagulants in this patient population,” going on to state that direct oral anticoagulants experienced “a nearly 50% reduction in VTE recurrence rates, and a more than twofold reduction in hospitalisation for major bleeding compared with LMWH therapy.”