Temporal trends in first-line outpatient anticoagulation treatment for cancer-associated venous thromboembolism.

BACKGROUND: First-line treatment and secondary prevention of venous thromboembolism (VTE) in patients with cancer consisted, historically, of unfractionated heparin or low-molecular weight heparin (LMWH). With recent clinical trials of direct oral anticoagulants (DOAC) showing similar efficacy as LMWH, little is known about anticoagulant prescribing patterns in patients with cancer and a VTE. This study characterized the temporal trends in first-line outpatient anticoagulation therapy for cancer-associated VTE. MATERIALS AND METHODS: This retrospective cohort study of patients who were hospitalized for a cancer-associated venous thromboembolism (VTE) between 01/01/2000 and 10/31/2017 identified patients from the cancer registries at two regions of an integrated healthcare delivery system. The primary outcome was the trend in age- and sex-adjusted rates of first-line anticoagulant therapy during the 30 days post-hospital discharge. Therapies were categorized as 1) injectable LMWH monotherapy, 2) warfarin ± injectable, 3) injectable fondaparinux monotherapy, or 4) DOAC ± injectable. RESULTS: Overall, 9816 patients were included with a mean age of 66 ± 13 years and 54% were female. From 2000 to 2003, warfarin ± injectable was used in ≈90% of cases. After 2003, there was a steady decline in warfarin use (25% in 2017) corresponding with increased LMWH use: 11% in 2003 to 55% in 2017. The DOAC ± injectable use has rapidly increased from <1% in 2014 to 20% in 2017. CONCLUSIONS: From 2000 to 2017, first-line anticoagulant therapy for cancer-associated VTE has experienced a substantial increase in LMWH and DOAC use with a resultant decline in warfarin use.