Use of Anticoagulation Among Patients With Atrial Fibrillation or Atrial Flutter in the United States

BACKGROUND: Oral anticoagulation (OAC) remains underused in patients with atrial fibrillation or flutter at high risk of ischemic stroke. We aimed to characterize documented OAC prescribing at diagnosis and during 1-year follow-up and identify factors associated with baseline OAC prescribing. The primary outcomes were documented OAC prescription at baseline and during 1-year follow-up. Exposures included demographic, clinical, and health-system characteristics. Multivariable logistic regression was used to identify factors associated with baseline OAC prescribing and loss of documented OAC prescribing during follow-up. RESULTS: Among 161 295 patients (median age, 76 years [interquartile range, 68-82]; 70 327 [43.6%] women), 92 518 (57.4%) had a documented OAC prescription at baseline, increasing from 56.6% in 2015 to 62.6% in 2019. Among those with a documented baseline OAC prescription, 45.6% had no documented OAC prescription during 1-year follow-up. Among 68 777 patients without a documented baseline OAC prescription, 12.5% had an OAC prescription documented during follow-up. Dementia (odds ratio, 0.58 [95% CI, 0.56-0.61]), prior major bleeding (odds ratio, 0.69 [95% CI, 0.63-0.75]), and renal disease (odds ratio, 0.84 [95% CI, 0.81-0.88]) were associated with lower odds of baseline OAC prescribing, whereas heart failure was associated with higher odds (odds ratio, 1.40 [95% CI, 1.37-1.43]). CONCLUSIONS: Among patients with newly diagnosed atrial fibrillation at high risk for ischemic stroke, OAC prescribing at diagnosis was suboptimal, and loss of documented OAC prescribing was common during the first year. Baseline OAC use was more strongly associated with bleeding risk, frailty, and comorbidity burden, and less consistently aligned with ischemic stroke risk.