Poor Time in Therapeutic Range Control is Associated with Adverse Clinical Outcomes in Patients with Non-Valvular Atrial Fibrillation: A Report from the Nationwide COOL-AF Registry.

BACKGROUND: Warfarin remains the most commonly used oral anticoagulant (OAC) in Thailand for stroke prevention among patients with non-valvular atrial fibrillation (NVAF). The aim of this study was to investigate the relationship between time in therapeutic range (TTR) after warfarin initiation and clinical outcomes of NVAF. METHODS: TTR was calculated by the Rosendaal method from international normalized ratio (INR) data acquired from a nationwide NVAF registry in Thailand. Patients were followed-up every six months. The association between TTR and clinical outcomes was analyzed. RESULTS: There was a total of 2233 patients from 27 hospitals. The average age was 68.4 ± 10.6 years. The average TTR was 53.56 ± 26.37%. Rates of ischemic stroke/TIA, major bleeding, ICH, and death were 1.33, 2.48, 0.76, and 3.3 per 100 person-years, respectively. When patients with a TTR < 65% were compared with those with TTR ≥ 65%, the adjusted hazard ratios (aHR) for the increased risks of ischemic stroke/TIA, major bleeding, ICH, and death were 3.07, 1.90, 2.34, and 2.11, respectively. CONCLUSION: Poor TTR control is associated with adverse clinical outcomes in patients with NVAF who were on warfarin. Efforts to ensure good TTR (≥65%) after initiation of warfarin are mandatory to minimize the risk of adverse clinical outcomes.

Rate of anticoagulant use, and factors associated with not prescribing anticoagulant in older Thai adults with non-valvular atrial fibrillation: A multicenter registry.

OBJECTIVES: To investigate the rate of anticoagulant use, the reasons for not prescribing anticoagulant, and the factors associated with non-prescription of anticoagulant in older Thai adults with non-valvular atrial fibrillation. METHODS: A multicenter registry of patients with non-valvular atrial fibrillation was conducted during 2014 to 2017 in Thailand. Demographic, medical history, antithrombotic medication, non-antithrombotic medication, and laboratory data were collected and analyzed. Data were compared between the older adult (≥ 65 years) and younger adult (< 65 years) groups. The reasons why anticoagulant was not prescribed were collected, and predictive factors were identified. RESULTS: A total of 3218 patients (1873 males) with an average age of 67.3 ± 11.3 years were included. Almost two-thirds (61.0%) of patients were in the older adult group. Anticoagulant was prescribed in 2422 patients (75.3%): 81.4% in the older adult group and 65.7% in the younger adult group. The three main reasons for not prescribing anticoagulant were already taking antiplatelets, patient refusal, and bleeding risk. These reasons were more common in older adults as compared to younger adults. Multivariate analysis revealed current use of antiplatelets to be the most important factor that predict the non-prescription of anticoagulant in older population. CONCLUSIONS: The prevalence of anticoagulant prescription among older Thai adults with atrial fibrillation is 81.4%. Taking antiplatelet drugs was found to be the strongest reason that predicts the non-prescription of anticoagulant in this patient population. A guideline should be developed to optimize the use of anticoagulant and antiplatelet in older adults.