Comparative Clinical and Economic Outcomes among Venous Thromboembolism Patients who Initiated Apixaban or Warfarin in the United States Medicare Population (VTE CER in Medicare)

Study type

• Study topic:
  Human medicinal product
• Study type:
  Non-interventional study
• Scope of the study:
  Effectiveness study (incl. comparative)

  Safety study (incl. comparative)

  Healthcare resource utilisation
• Data collection methods:
  Secondary use of data

Non-interventional study

• Non-interventional study design:
  Cohort

Study drug and medical condition

• Name of medicine:
  ELIQUIS

Population studied

• Short description of the study population:
  Elderly (≥65 years) patients diagnosed with Venous thromboembolism (VTE) in the Medicare population, who were prescribed apixaban or warfarin (bridging to warfarin) between September 1, 2014 and December 31, 2016 and had continuous health plan enrolment for 6 months prior to the prescription.
• Age groups:
  Adults (65 to < 75 years)

  Adults (75 to < 85 years)

  Adults (85 years and over)
• Special population of interest:
  Other
• Special population of interest, other:
  Venous thromboembolism patients
• Estimated number of subjects:
  1

Study design details

• Main study objective:
  Aim 1: Compare the demographic and clinical characteristics of patients who were prescribed apixaban or warfarin. Aim: 2: Compare both the incidence rates and the risk (using Hazard ratios) of major bleeding between patients who received apixaban versus warfarin.Aim 3: Compare both the incidence rates and the risk of CRNM between patients who received apixaban versus warfarinAdditional
• Outcomes:
  Major bleeding, CRNM bleeding, Recurrent VTE, Major bleeding related costs, Recurrent VTE related cost, All cause health care utilization, All cause costs, All cause death
• Data analysis plan:
  Means, medians, and standard deviations will be provided for continuous variables. Numbers and percentages will be provided for dichotomous and polychotomous variables. Bivariate comparisons of baseline characteristics and outcomes measures will be provided. Appropriate tests (eg, t-test, chi-square test) will be used based on the distribution of the measure. The cumulative incidence rate for clinical outcomes (major bleeding, CRNM, and recurrent VTE) will be calculated. Propensity score matching will be used to balance patient characteristics of the cohorts. Cox regression models will be used to evaluate the risk of clinical outcomes. Generalized linear models (GLM) and two-part models will be used to compare health care costs between the apixaban and warfarin cohorts. Data analysis will be executed using statistical software SAS version 9.3/9.4.