A retrospective cohort study of Thai octogenarians with nonvalvular atrial fibrillation (NVAF) initiating apixaban, dabigatran, rivaroxaban or warfarin was conducted in medical school hospital in Thailand. Patients were recruited from January 1, 2013, to December 31, 2018. The efficacy outcome was early recurrence of stroke or transient ischemic attack (TIA) in 90 days after initiation of oral anticoagulants (OACs). The safety outcome were major bleeding and clinically relevant non-major bleeding complications in 180 days. Continuous variables were compared using independent t test and MannWhitney U test, and categorical variables were compared using chi-square test or Fisher's exact test. Furthermore, hazard ratios and P values were calculated by the use of multivariable Cox's regression analysis.

This is a retrospective cohort study of Thai octogenarians with NVAF. Patients who were prescribed with apixaban, dabigatran, edoxaban, rivaroxaban or warfarin from January 1, 2013, to December 31, 2018 were recruited. The primary efficacy was recurrent ischemic stroke or TIA in 90 days after initiating OACs. The secondary efficacy were recurrent ischemic stroke or TIA in 180 days after initiating OACs. While any bleeding complications were defied as primary safety outcomes. Continuous variables were compared using independent t test and MannWhitney U test, and categorical variables were compared using chi-square test or Fisher's exact test.

Inclusion Criteria:

• Age more than 80 years old
• Patients who were diagnosed with I48, I63 or G45 from International Classification of Diseases 10th version (ICD-10). Patients who were diagnosed atrial fibrillation and flutter, cerebral infarction or transient cerebral ischemic attacks (TIA) and related syndromes)
• Patients were prescribed apixaban, dabigatran, edoxaban, rivaroxaban, or warfarin

Exclusion Criteria:

• Patients were prescribed oral anticoagulants for other indications

  1. Prophylaxis thromboembolic events in valvular atrial fibrillation
  2. Treatment of venous thromboembolism
  3. Prophylaxis thromboembolic events in hip or knee replacement

• Patients who had contraindication to oral anticoagulants

  1. Creatinine clearance calculated from Cockcroft-Gault equation 1.1 Creatinine clearance less than 30 mL/min (for patients who receiving Dabigatran) 1.2 Creatinine clearance less than 15 (mL/min (for patients who receiving Apixaban, Edoxaban, Rivaroxaban)
  2. Patients were diagnosed acute hepatitis, chronic active hepatitis

Patients aged over 80 years with non valvular atrial fibrillation who were prescribed oral anticoagulants (OACs) which were apixaban, dabigartran, edoxaban, rivaroxaban and warfarin for stroke secondary prevention.

Primary outcome of this study