Abstract 263: Real World Outpatient Treatment Patterns of Patients with Cancer-Associated Venous Thromboembolism in the US

Abstract

Objective: The aim of the study is to describe post-discharge treatment patterns in patients with cancer-associated venous thromboembolism (VTE) following an emergency department (ED) visit or inpatient (IP) admission. Methods: Adults (≥ 18 years) with VTE diagnosed during an ED or IP visit with a cancer diagnosis, and their respective VTE treatments were identified from the IQVIA Real-World Data Adjudicated Claims - US TM database between 7/1/15 and 6/30/17. Initial outpatient (OP) treatment received within 6 months post-discharge was assessed. Treatment duration, adherence, persistence, and switching were evaluated over variable follow-up in patients who had ≥ 6 months of continuous health plan eligibility after initiation of OP therapy. Results: A total of 3,064 cancer-associated VTE patients (54% female; mean age 54.3 [SD=9.9] years) were included. 53% were diagnosed with VTE in the ED and 47% IP. The most common initial post-discharge OP treatments observed were direct-acting oral anti-coagulants (DOACs; 37%), low molecular weight heparin (LMWH; 30%), and warfarin (12%); 10% of patients had no evidence of treatment within 6-months of discharge. Median follow-up after treatment initiation was 412 days among the 2,698 patients who had at least 6 months of follow-up after initiation of post-discharge therapy. Duration of treatment (allowable gap=60 days) was longest with DOACs (231.5 days [SD=183.1]), followed by warfarin (223.0 days [SD=200.0] and LMWH (138.3 days [SD=138.2]. Adherence to initial treatment prior to discontinuation was high across all therapies, with 80% of patients having a medication possession ratio (MPR) ≥ 80%. The proportion of patients who remained on therapy for ≥ 6 months was highest among patients who initiated DOACs (55%), followed by warfarin (51%) and LMWH (33%) patients. A total of 1,597 (59%) patients discontinued their initial post-discharge treatment within 6 months of initiation, with an average time to discontinuation of 87.5 days (SD=53.4) for DOACs, 76.7 days (SD=51.6) for warfarin patients, and 61.3 days (SD=49.3) for LMWH. Among these, 30%, 54%, and 65% of DOAC, warfarin, and LMWH patients, respectively, switched to a new OP treatment. Patients who initiated OP therapy with DOACs were most likely to switch to LMWH (33%) or warfarin (21%), while those who initiated therapy with warfarin or LMWH were most likely to switch to DOACs after discontinuation (74% and 70%, respectively). Conclusions: This real-world study showed that DOACs or LMWH were the most common initial post-discharge therapies for cancer-associated VTE. Although treatment adherence was high, only DOAC and warfarin patients had a 6-month persistence rate on initial treatment ≥ 50%. Switching was most common in patients treated with warfarin or LMWH, most of whom switched to DOACs.