Oral anticoagulants (OACs) mitigate stroke risk in patients with atrial fibrillation (AF). The study aim was to analyze prevalence and predictors of OAC underutilization.


Newly diagnosed AF patients with a CHA2DS2-VASc score ≥ 2 were identified from the US CMS Database (January 1, 2013–December 31, 2017). Patients were stratified based on having an OAC prescription versus not and the OAC prescription group was stratified by direct OAC (DOACs) versus warfarin. Multivariable logistic regression models were used to examine predictors of OAC underutilization.


Among 1,204,507 identified AF patients, 617,611 patients (51.3%) were not prescribed an OAC during follow-up (mean: 2.4 years), and 586,896 patients (48.7%) were prescribed an OAC during this period (DOAC: 388,629 [66.2%]; warfarin: 198,267 [33.8%]). Age ≥ 85 years (odds ratio [OR] 0.55, 95% confidence interval [CI] 0.55–0.56), female sex (OR 0.96, 95% CI 0.95–0.96), Black race (OR 0.78, 95% CI 0.77–0.79) and comorbidities such as gastrointestinal (GI; OR 0.43, 95% CI 0.41–0.44) and intracranial bleeding (OR 0.29, 95% CI 0.28–0.31) were associated with lower utilization of OACs. Furthermore, age ≥ 85 years (OR 0.92, 95% CI 0.91–0.94), Black race (OR 0.78, 95% CI 0.76–0.80), ischemic stroke (OR 0.77, 95% CI 0.75–0.80), GI bleeding (OR 0.73, 95% CI 0.68–0.77), and intracranial bleeding (OR 0.72, 95% CI 0.65–0.80) predicted lower use of DOACs versus warfarin.


Although OAC therapy prescription is the standard of care for stroke prevention in AF patients, its overall utilization is still low among Medicare patients ≥ 65 years old, with specific patient characteristics that predict underutilization.


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