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. Underprescription 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 CHA(2)DS(2)-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 CHA(2)DS(2)-VASc score and higher risk of thromboembolic events. Anemia, lower body weight, and aspirin use were characteristics associated with warfarin under-prescription.