Anticoagulation Strategies for the Treatment of Acute Venous Thromboembolism in Medicare Fee For-Service Patients With End-Stage Renal Disease Using USRDS Data

The investigators will perform a retrospective cohort analysis using USRDS data from 2014 through 2018 and a descriptive serial cross-sectional analysis using USRDS data from 2009 through 2018 to evaluate the investigators' aims. USRDS data will be utilized to address all the research aims.

Primary Objective To compare rates of major bleeding attributable to initiation of treatment with apixaban relative to warfarin among patients with ESRD and acute VTE The primary safety outcome will be rates of major bleeding within 6 months of VTE diagnosis as defined by Cunningham, which is a standardized definition of major bleeding that can be derived from administrative data and is based on clinical bleeding definitions from a number of clinical trials. A secondary safety outcome will be gastrointestinal bleeding within 6 months of VTE diagnosis.

Secondary Objectives To describe contemporary anticoagulation strategies to treat acute VTE in ESRD patients and changes over the last decade The investigators will report rates of use of anticoagulation strategies [warfarin, low molecular weight heparin (LMWH), and DOACs (apixaban, edoxaban, rivaroxaban, and dabigatran)] in this ESRD population. The investigators will examine rates of these strategies by year to examine changes in adoption of various strategies over time as DOACs have become available for VTE treatment.

To compare rates of recurrent VTE attributable to initiation of treatment with apixaban relative to warfarin among patients with ESRD and acute VTE The primary outcome will be recurrent VTE within 6 months of VTE diagnosis. All-cause mortality within 6 months of VTE diagnosis will be evaluated as an exploratory endpoint.

To compare healthcare resource utilization from 15 days before to 90 days after first prescription date attributable to initiation of treatment with apixaban relative to warfarin among patients with ESRD and acute VTE The primary outcome will be total inpatient days from 15 days before to 90 days after first prescription date. In addition to total inpatient days, the investigators will also compare emergency department (ED) utilization after initiation of anticoagulation across treatment strategies. By incorporating 15 days prior to first prescription date, the investigators will capture hospitalization days that were associated with the index VTE diagnosis, given that the first anticoagulation prescription would likely be written at the time of hospital discharge for those patients who are hospitalized.