Characteristics of warfarin under-prescription in older adults with atrial fibrillation

Background: The prevalence of atrial fibrillation (AF) and atrial flutter (AFl) increases with age. Under-prescription of anticoagulants in older adults can lead to increased morbidity and mortality. We analyzed warfarin prescription patterns in older adults. Methods: In this observational single-center study, we analyzed 2179 consecutive patients with admission diagnosis of AF or AFl. Patients were divided into “older” (≥ 75 years old) and “younger” (<75 years old) groups. Prescription patterns of warfarin were analyzed. Patients discharged from the hospital on a non-warfarin anticoagulation were excluded. Results: Of the 1988 patients analyzed, 46.9% were ≥75 years old, of which 50.8% were prescribed warfarin. There was no association between mean CHA₂DS₂-VASc score and warfarin prescription on discharge (OR = 1.06 (95% CI 0.93–1.21), p = 0.388) in the older group. After adjusting for hypertension, renal function, and Black race, warfarin prescription in older adults was independently associated with lower aspirin prescription rates (OR = 0.57 (95% CI 0.43–0.75), p < 0.001), lower body mass index (OR = 1.03 (95% CI 1.01–1.06), p = 0.018), and lower hemoglobin levels (OR = 1.11 (95% CI 1.04–1.19), p = 0.002). Conclusions: In our study, older adults (≥75 years old) with AF and AFl tended to have lower rates of warfarin prescription despite higher CHA₂DS₂-VASc score and higher risk of thromboembolic events. Anemia, lower body weight, and aspirin use were characteristics associated with warfarin under-prescription.