Safety and Effectiveness of Apixaban in Very Elderly Patients With Non-valvular Atrial Fibrillation (NVAF) Compared to Warfarin Using Administrative Claims Data

Safety and Effectiveness of Apixaban in Very Elderly Patients With NVAF Compared to Warfarin Using Administrative Claims Data

The objective of this study is to investigate safety and effectiveness of apixaban compared to warfarin in very elderly patients with Non-valvular atrial fibrillation (NVAF). In addition to the absolute age, effects on higher age-related risk factors on relative risk of apixaban to warfarin is also investigated through subgroup analyses.

This is a retrospective non-intervention observational study to evaluate the difference in safety and effectiveness between apixaban and warfarin using a database provided by Medical Data Vision Co. Ltd. (MDV Co. Ltd.). Eligible patients will be extracted from the database and allocated to the pre-defined cohorts based on the actual age, age of NVAF diagnosis and types of anticoagulant therapy.

Patient characteristics will be balanced by an Inverse probability of treatment weighting (IPTW) method, and risk of stroke/SE (primary effectiveness endpoint) and major bleeding (primary safety endpoint) will be compared.

Inclusion Criteria:

• Patients must meet all the following inclusion criteria to be eligible for inclusion in the study.

  1. Diagnosed with Atrial fibrillation (AF) anytime in the baseline period or on the index date, also have definitive diagnosis of AF anytime in the baseline period, on the index date, or post-index period.
  2. Prescribed apixaban or warfarin on or after the day of AF diagnosis. The first observed prescription will be used to identify the patient's index date and treatment cohort
  3. No use of the any Oral anticoagulants (OAC)s during the baseline period (the 180 days before the index date)
  4. Age of 18 years or older on the index date.
  5. Index date is at age 80 or older

Exclusion Criteria:

• Patients meeting any of the following criteria will not be included in the study:

  1. Having a diagnosis of valvular atrial fibrillation, post-operative atrial fibrillation, rheumatic atrial fibrillation or mechanical-valvular atrial fibrillation during the baseline and post-index period
  2. Having a cardiac surgery procedure record during the baseline period
  3. Having a joint replacement procedure record during the baseline period
  4. Having a procedure of prosthetic heart valve during the baseline period
  5. Having a diagnosis of venous thromboembolism during the baseline period
  6. Female patients with pregnancy during the follow-up period
  7. Patients prescribed "off-label" doses of OACs (per Japanese package insert of each OAC) or patients treated with OAC but in "off-label" or "contraindicated" manners.