Characteristics of patients with atrial fibrillation treated with direct oral anticoagulants and new insights into inappropriate dosing: results from the French National Prospective Registry: PAFF.

AIMS: Since the introduction of direct oral anticoagulant (DOAC) for atrial fibrillation (AF) therapy, inappropriate and/or underdosing of these drugs has been a major clinical challenge. We evaluated the characteristics of patients with AF treated with inappropriate and low-dose DOACs. METHODS AND RESULTS: Patients with AF treated with inappropriate and low-dose DOACs from October 2021 to December 2021 were evaluated from the French National Prospective Registry (PAFF). We evaluated 1890 patients with AF receiving DOACs (apixaban 55%, dabigatran 7%, and rivaroxaban 38%). Inappropriate dosing was noted in 18% of the population. Patients with appropriate dosing had less comorbidities: younger age (75 ± 10 vs. 82 ± 8 years old, P < 0.0001), reduced chronic renal failure (26 vs. 61%, P < 0.0001), and lower CHA2DS2VASc and HASBLED scores (3 ± 2 vs. 4 ± 3, P < 0.0001; 2 ±1 vs. 2 ± 2, P < 0.0001), respectively. In multivariate analysis, older age (P < 0.0001) and a higher CHA2DS2VASc score (P = 0.0056) were independently associated with inappropriate DOAC dosing. Among 472 patients (27%) treated with low-dose rivaroxaban or apixaban, 46% were inappropriately underdosed. Patients inappropriately underdosed were younger (82.3 ± 8.4 vs. 85.9 ± 5.9 years, P < 0.0001) with less chronic renal disease (47 vs. 98%, P < 0.0001). However, these patients had higher rates of prior haemorrhagic events (18 vs. 10%, P = 0.01), clopidogrel use (11 vs. 3%, P = 0.0002), and apixaban prescription (74 vs. 50%, P < 0.0001). CONCLUSION: Within this large registry, DOACs were associated with inappropriate dosing in 18% of cases. Independent predictors of inappropriate dosing were high CHA2DS2VASc scores and older age. Moreover, 46% of patients treated with low-dose DOACs were inappropriately underdosed and more frequently in patients treated with apixaban.

Determinants of Antithrombotic Treatment for Atrial Fibrillation in Octogenarians: Results of the OCTOFA Study.

BACKGROUND AND OBJECTIVE: Atrial fibrillation, the most frequent form of arrhythmia, affects 5-15% individuals aged > 80 years. Stroke is a major risk for atrial fibrillation patients. The benefits of anticoagulant therapy clearly outweigh the risk of hemorrhage, even in the elderly. Despite the efficacy of warfarin, many eligible patients receive no prophylactic antithrombotic therapy. New generation oral anticoagulants compare favorably with vitamin K antagonists in the prevention of thromboembolic events and hemorrhage. These new agents are likely to influence the prescribing habits of anticoagulants in atrial fibrillation. The aim of this study to investigate both the frequency and the determining factors of anticoagulant prescriptions in AF patients aged ≥ 80 years and followed up by private-practice cardiologists in France. METHODS: The OCTOFA (Atrial Fibrillation in Octogenarians) Study assessed the anticoagulant prescribing habits of cardiologists in France. The volunteer cardiologists recruited all consecutive patients fulilling the inclusion criteria. RESULTS: Between June 2013 and September 2016, 89 cardiologists recruited 738 eligible patients: age ≥ 80 years, non-valvular atrial fibrillation, no other compelling indication for anticoagulation therapy, no recent acute coronary syndrome or stroke. Most (90.7%) patients were on oral anticoagulant therapy: vitamin K antagonist or non-vitamin K antagonist oral anticoagulants, low molecular weight heparin (1.4%), aspirin (5.7%), and no antithrombotic treatment (2.2%). Patients on vitamin K antagonists were older (p < 0.001), had lower renal function (p = 0.033), and had a more frequent history of myocardial infarction (p < 0.001), heart failure (p = 0.001), peripheral artery disease (p = 0.033), major hemorrhage (p = 0.025), and falls (p = 0.045). Four determining factors of anticoagulant prescriptions were statistically significant: high CHA2DS2-VASc score (p < 0.001), high HAS-BLED score (p < 0.001), age > 90 years (p = 0.001), and moderate/severe cognitive impairment (p = 0.002). CONCLUSIONS: Most private-practice cardiologists prescribe anticoagulant treatment according to current guidelines in elderly atrial fibrillation patients. Non-vitamin K antagonist oral anticoagulants represent a significant proportion of prescriptions.