Abstract 52: Association of Heparin Lead-in Therapy and Recurrence in the Treatment of Venous Thromboembolism

Abstract

Background: Venous thromboembolism (VTE) encompasses deep vein thrombosis (DVT) and pulmonary embolism (PE). Anticoagulant treatment significantly decreases the risk of recurrent VTE events and is typically initiated with the administration of a heparin therapy along with warfarin followed by warfarin treatment alone. The objective of this study was to assess the association between heparin lead-in therapy and VTE recurrence in patients receiving warfarin. Methods: Data from adult patients who had a VTE diagnosis in a large claims database (period 2005 - 2011), a warfarin claim within 30 days and continuous eligibility for at least 12 months pre/post first (index) diagnosis, were analyzed. Patients with atrial fibrillation, VTE, or treatment with warfarin therapy prior to the index date were excluded. Patients were classified into 4 cohorts: 1) Outpatient DVT; 2) Outpatient PE; 3) Inpatient DVT; 4) Inpatient PE. Inpatient cohort patients had an index inpatient VTE claim or had an inpatient VTE claim within 7 days of an index outpatient VTE claim. Outpatient cohort patients were required to have another outpatient VTE claim within 7 days of their index claim. Patients with both DVT and PE claims were included in the PE cohorts. Recurrent VTE was defined as the presence of an inpatient VTE claim within 365 days from the index date. Heparin use was identified by a UFH/LMWH pharmacy claim within 7 days of the outpatient index date or discharge from an inpatient VTE index event. Cox proportional hazard models adjusting for age, gender, health insurance type and baseline Elixhauser comorbidities were used. Results: A total of 39,424 patients met study criteria. Mean (SD) age was 59.8 (15.6) years and 50.6% (19,946/39,424) were female. Most patients (72.0%; 28,388/39,424) had an index inpatient event with a mean (SD) LOS=5.4 (4.1) days. Outpatient DVT/PE patients who used heparin had significantly lower rates of VTE recurrence vs. those who did not ( P <0.05). Post-discharge heparin use was not associated with VTE recurrence rates within inpatient cohorts. Conclusion: The use of heparin lead-in therapy can significantly reduce VTE recurrence in the Outpatient VTE cohorts. Due to the lack of inpatient drug use data to identify heparin use in this claims database, additional studies are needed to confirm our Inpatient cohort results.