Starting dose and dose adjustment of non-vitamin K antagonist oral anticoagulation agents in a nationwide cohort of patients with atrial fibrillation.

This study aims to provide real-world data about starting-dose of NOACs and dose-adjustment in patients with atrial fibrillation (AF). In fact, even if new oral anticoagulation agents (NOACs) have a predictable effect without need for regular monitoring, dose-adjustments should be performed according to the summary of product information and international guidelines. We employed the Italian Medicines Agency monitoring registries comprising data on a nationwide cohort of patients with AF treated with NOACs from 2013 to 2018. Logistic regression analysis was used to evaluate the determinants of dosage choice. During the reference period, treatment was commenced for 866,539 patients. Forty-five percent of the first prescriptions were dispensed at a reduced dose (dabigatran 60.3%, edoxaban 45.2%, apixaban 40.9%, rivaroxaban 37.4%). The prescription of reduced dose was associated with older age, renal disease, bleeding risk and the concomitant use of drugs predisposing to bleeding, but not with CHA2DS2-VASc and HAS-BLED. A relative reduction of the proportion of patients treated with low dosages was evident overtime for dabigatran and rivaroxaban; whereas prescription of low dose apixaban and edoxaban increased progressively among elderly patients. Evidence based on real-world data shows a high frequency of low dose prescriptions of NOACs in AF patients. Except for older age, renal disease, bleeding risk and the concomitant use of drugs predisposing to bleeding, other factors that may determine the choice of reduced dose could not be ascertained. There may be potential under-treatment of AF patients, but further evaluation is warranted.

Non-vitamin K antagonist oral anticoagulation agents in patients with atrial fibrillation: Insights from Italian monitoring registries.

BACKGROUND: Atrial fibrillation (AF) is the most common cardiac arrhythmia associated with an increased risk of stroke and thromboembolism. Anticoagulation with Vitamin K antagonists (VKAs) or with novel oral anti-coagulants (NOACs) represents the cornerstone of the pharmacological treatment to reduce the risk of thromboembolism. This study aims to provide real-world data from a whole large European country about NOAC use in "non-valvular atrial fibrillation" (NVAF). METHODS: We analysed the Italian Medicines Agency (AIFA) monitoring registries collecting data of a nationwide cohort of patients with "NVAF" treated with NOACs. Using logistic regression analysis, baseline characteristics and treatment discontinuation information were compared among initiators of the 4 NOACs. RESULTS: In the reference period, the NOAC database collected data for 683,172 patients. The median age was 78 years with 19.5% aged 85 or older. Overall, the treatments were in accordance with guidelines. About 1/3 of patients switched from a prior VKA treatment; in the 72.3% of cases, these patients had a labile International Normalized Ratio (INR) at first prescription. The most prescribed NOAC was rivaroxaban, followed by apixaban, dabigatran and edoxaban. CONCLUSIONS: This study is the largest European real-world study ever published on NOACs. It includes all Italian patients treated with NOACs since 2013 accounting for about 1/3 of subjects with AF. The enrolled population consisted of very elderly patients, at high risk of ischemic adverse events. The AIFA registries are consolidated tools that guarantee the appropriateness of prescription and provide important information for the governance of National Health System by collecting real-world data.