Prescribing of oral anticoagulants in the emergency department and subsequent long-term use by older adults with atrial fibrillation

Background: Patients with atrial fibrillation frequently seek emergency care. Rates of guideline-concordant oral anticoagulant therapy for stroke prevention are suboptimal in the community. We assessed the association between prescribing of oral anticoagulants in the emergency department (relative to referral to a longitudinal care provider for treatment initiation) and long-term use of oral anticoagulants.

Methods: This retrospective cohort study performed at 15 hospitals in Ontario, Canada, involved patients aged 65 years or older who visited the emergency department between 2009 and 2014, who had a primary diagnosis of atrial fibrillation, were discharged home, and were eligible for and willing to take stroke-prevention therapy. We used inverse probability-of-treatment weighting based on the propensity score to compare patients who were and were not given a prescription for an oral anticoagulant. The primary outcome was a prescription fill for an oral anticoagulant 6 months later. Secondary outcomes included a prescription fill at 1 year, all-cause mortality, and strokes or bleeding events leading to hospital admission.

Results: Of 2132 eligible patients, 402 (18.9%) were given a prescription for an oral anticoagulant in the emergency department. After weighting, 67.8% of these patients had filled a prescription for an oral anticoagulant at 6 months versus 37.2% of those who did not receive a prescription in the emergency department (absolute risk increase [ARI] 30.6%, number needed to treat [NNT] 3). At 1 year, the ARI was 23.2% and the NNT was 4. Rates of death, stroke and bleeding events did not differ significantly.

Interpretation: In patients with atrial fibrillation who were eligible for stroke prevention, prescribing an oral anticoagulant in the emergency department was associated with substantially higher long-term use of oral anticoagulants compared with deferring to the longitudinal care provider to initiate this therapy. Physicians working in the emergency department should consider initiating oral anticoagulation in eligible patients who are being discharged to home.