Introduction: Non-valvular atrial fibrillation (NVAF) is the most common cardiac arrhythmia and it is associated with a 5-fold increase in risk of ischemic stroke. Although clinical guidelines recommend antithrombotic therapy for stroke prevention in patients at moderate or high risk for stroke, little is known on the extent to which the increase of the risks influence the choice of the therapy.
Aim: The aim of the study was to assess the level of adherence to the guidelines for the prevention of thromboembolic risk in patients with NVAF.
Methods: A population-based cohort study was conducted using administrative data from a local health authority in the Campania Region (~1,000,000 inhabitants). NVAF was defined as one or more claims for atrial fibrillation between July, 2013 and June, 2014 where none of the claims were associated with cardioversion or cardiac ablation during the identification period and there was no evidence of valve-related diagnoses or procedures. The cohort was classified according to the first drug dispensing during 6 months from the discharge date for atrial fibrillation. Patients were categorized in low ischemic stroke risk (LR, score = 0), moderate-risk (MR, score = 1), high-risk (HR, score≥2) according to the CHA2DS2-VASc score. Multivariable logistic regression was used to evaluate the associations between ischemic stroke risk with the choice of non-vitamin K antagonist oral anticoagulants (NOACs) versus vitamin K antagonists (VKAs) therapy.
Results: A total of 1963 patients were identified: 4.9% LR, 7.6% MR and 87.5% HR patients. Overall, 36.4% of patients were not treated (LR: 56.7%, MR: 55.0%, HR: 33.7%patients). The Vitamin K antagonists were prescribed to 17% of the patients (LR: 10.3%, MR: 12,1%, HR: 17,8%), NOAC to 12,7% (LR: 10,3%, MR: 8,1%, HR: 13,2%), low-dose aspirin to 17.5% (LR: 13,4%, MR: 15,4%, HR: 17,9%), other antiplatelet to 12,3% (LR: 7,2%, MR: 6,0%, HR: 13,2%). The ischemic stroke was not significantly associated with the choice of anticoagulant drug.
Conclusions: High proportion of NVAF patients with CHA2DS2-VASc score of 2 or greater not received oral anticoagulant as recommended. In contrast with recent guidelines, aspirin was commonly prescribed even in HR patients. The stroke risk stratification did not influence the choice of anticoagulant drug.