Abstract
Background/Aims Injectible low-molecular-weight heparin (LMWH) monotherapy is recommended over other anticoagulant therapies (e.g., oral warfarin + injectible anticoagulant) for venous thromboembolism (VTE) in cancer patients based on superior clinical outcomes. The aim of this retrospective study was to evaluate the extent of use of LMWH for cancer patients with incident post-cancer diagnosis VTE.
Methods Patients aged =21 years with stage III and IV breast, colorectal, lung, and prostate cancer diagnosed between 2000–2007 at five Cancer Research Network (CRN) sites and diagnosed with VTE within two years of cancer diagnosis who received outpatient VTE treatment were included. Patient characteristics, clinical information, pharmacy and healthcare utilization, and mortality were obtained from the CRN Virtual Data Warehouse. Patients were followed for one year after VTE diagnosis. Outcomes include the rates of initial anticoagulant(s) treatment within seven days of VTE diagnosis, VTE recurrence, and post-treatment bleeding. Logistic regression was used to identify factors associated with LMWH choice.
Results Data for 662 cancer patients from three study sites were available. Patients were primarily =65 years (52%, 347/662), male (52%, 347/662), diagnosed with stage IV cancer (54%, 360/662), lung cancer (51%, 338/662), received chemotherapy prior to VTE diagnosis (64%, 425/662), and had a mean Charlson-Deyo risk score of 1.6 (±1.5). Only 29% (195/662) of patients received LMWH monotherapy while 69% (456/662) and 2% (11/662) received warfarin + an injectible anticoagulant and injectible foundaparinux, respectively. Recurrent VTE occurred in 1.6% (3/195) vs. 3.3% (15/456) of patients who received LMWH monotherapy vs. warfarin + injectible anticoagulant, respectively (p=0.298). Bleeding rates were similar across treatment groups (p=0.710). Factors independently associated with LMWH monotherapy treatment choice include stage IV cancer, lung cancer, reception of chemotherapy, and history of VTE diagnosis prior to cancer diagnosis.
Conclusions Adherence to evidence-based treatment recommendations for VTE in cancer patients was low. Future studies will analyze the data from all participating sites and should evaluate rationale(s) for patient/provider preference for LMWH monotherapy.
