Anticoagulant therapy beyond primary treatment among active cancer and non-cancer patients with venous thromboembolism in the United States
Authors: Cohen A T , Dhamane A D , Liu X , Han S , Stellhorn R , Singh R , Wang J , Zhang Q , Luo X 
Published: November 2023

Abstract

Background
European Society of Cardiology (ESC) and American Society of Hematology (ASH) guidelines recommend anticoagulant (AC) therapy for ≥3 months among patients with major persistent risk factors such as cancer to prevent recurrent venous thromboembolism (VTE).

Purpose
To describe AC use beyond the primary treatment period (3 months) among Active Cancer and non-Cancer patients with VTE. Demographics and clinical profiles were also evaluated for these patients.

Methods
This retrospective observational study included VTE patients ≥18 years from a US large administrative claims database (01/01/2017 – 04/30/2022). Patients who initiated AC treatment (apixaban, dabigatran, rivaroxaban, warfarin, or low molecular weight heparin [LMWH]) within 30 days of index VTE event were selected and the treatment start date was defined as the AC initiation date. Active Cancer and non-Cancer cohorts were created based on the presence or absence of cancer diagnosis or cancer treatment 6 months before or 30 days after the index VTE event. Patients were required to have continuous health plan enrollment (CE) 6 months prior and ≥3 months after the AC initiation date. The end of 3 months after the AC initiation was defined as index date. Patients with evidence of recurrent VTE and switch to a new AC during the primary treatment period were excluded. Continuous use of initial AC treatment for ≥3 months and baseline patient characteristics were assessed. The primary AC treatment duration was expanded to ≥6 months in a scenario analysis.

Results
The initial study population included 434,523 patients who initiated primary AC treatment within 30 days of index VTE; 19% (n=83,050) in the Active Cancer and 81% (n=351,473) in the non-Cancer cohorts. After the selection criteria were met, the Active Cancer cohort included 52,409 patients; of these, overall, 49.1% of patients received continuous primary AC treatment for ≥3 months (apixaban = 55.6%, dabigatran = 41.7%, rivaroxaban = 55.9%, LMWH = 26.9%, warfarin = 46.7%). Among patients in non-Cancer cohort (n=254,913), overall, 56.7% received continuous primary AC treatment for ≥3 months (apixaban = 59.0%, dabigatran = 49.2%, rivaroxaban = 57.7%, LMWH =20.1%, warfarin = 54.2%). For primary AC treatment duration of ≥6 months, type of AC use was consistent; however, the treatment rates were lower, for both Active Cancer (29.8%) and non-Cancer (34.8%) cohorts. (Figure 1). Patients in the Active Cancer cohort were older, had a higher comorbidity burden and higher % of patients with a history of bleeding compared to the non-Cancer cohort. (Figure 2).

Conclusion
About one-half (49.1%) of VTE patients with Active Cancer received ≥3 months of primary AC treatment; this proportion was higher (56.7%) in the non-Cancer cohort. Apixaban and rivaroxaban were the most prescribed anticoagulants. The study highlights potential gaps in guideline-recommended anticoagulation treatment among VTE patients in an extended treatment setting.Figure 1Figure 2