Evaluation of Apixaban for the Treatment of Nonvalvular Atrial Fibrillation With Regard to Dosing and Safety in a Community Hospital

Abstract

Background: Apixaban, a direct factor Xa inhibitor, is approved by the US Food and Drug Administration (FDA) for prevention of stroke and systemic embolism in nonvalvular atrial fibrillation. Apixaban’s compelling safety and efficacy data, combined with minimal laboratory monitoring, make it an attractive anticoagulant. Objectives: To characterize and evaluate the dosing and safety of apixaban for the treatment of nonvalvular atrial fibrillation at a community hospital. Design/Patients: A retrospective chart review evaluated patients ≥18 years of age who received at least 2 consecutive doses of apixaban from January 1, 2013 to June 30, 2016. Patients with multiple admissions were evaluated for each hospitalization. Patients were excluded if height, weight, or serum creatinine was not documented during hospital admission. Patients who received apixaban for the treatment or prophylaxis of venous thromboembolism were excluded. Prescribing patterns were characterized based on FDA-approved dosing regimens and patient demographics. Safety outcomes included incidences of major, clinically relevant nonmajor, and minor bleeding. Results: Of the 707 patients evaluated, 82% received an FDA-approved apixaban regimen. Of the 127 patients (18%) who received an unapproved regimen, 5.5% (7 patients) received an unapproved frequency and 94.5% (120 patients) received an unapproved dose. The majority (98 patients, 81.7%) were underdosed. Composite bleeding rates were 2.7%, with 1.8% major bleeds, 0.7% clinically relevant nonmajor bleeds, and 0.1% minor bleeds. Conclusions: The use of apixaban must be monitored in order to ensure FDA-approved dosing regimens are being prescribed and patients are not being underdosed.