Background and Purpose- Guideline adherent oral anticoagulant (OAC) management of patients with nonvalvular atrial fibrillation has been associated with improved outcomes, but limited data are available from Asia. We aimed to investigate outcomes in patients who received guideline compliant management compared with those who were OAC undertreated or overtreated, in a large nationwide multicenter cohort of patients with nonvalvular atrial fibrillation in Thailand. Methods- Patients with nonvalvular atrial fibrillation were prospectively enrolled from 27 hospitals-all of which are data contributors to the COOL-AF Registry (Cohort of Antithrombotic Use and Optimal INR Level in Patients With Non-Valvular Atrial Fibrillation in Thailand). Patients were categorized as follows: (1) guideline adherence group when OAC was given in high-risk or intermediate-risk, but not in low-risk patients; (2) undertreatment group when OAC was not given in the high-risk or intermediate-risk groups; and (3) overtreatment group when OAC was given in the low-risk group or when OAC was given in combination with antiplatelets without indication. Results- A total of 3327 patients who had follow-up clinical outcome data were included. The mean age of patients was 67.4 years and 58.1% were male. The numbers of patients in the guideline adherence group, undertreatment group, and overtreatment group were 2267 (68.1%), 624 (18.8%), and 436 (13.1%) patients, respectively. The overall rate of ischemic stroke, major bleeding, all bleeding, and death was 3.0%, 4.4%, 15.1%, and 7.8%, respectively. Undertreated patients had a higher risk of ischemic stroke and death compared with guideline adherent patients, and overtreated patients had a higher risk of bleeding and death compared with OAC guideline-managed patients. Conclusions- Adherence to OAC management guidelines is associated with improved clinical outcomes in Asian nonvalvular atrial fibrillation patients. Undertreatment or overtreatment was found to be associated with increased risk of adverse outcomes compared with guideline-adherent management.
Keywords: anticoagulants; atrial fibrillation; hemorrhage; hypertension; thromboembolism.