The Long-Term Use of Warfarin Among Atrial Fibrillation Patients Discharged From an Emergency Department With a Warfarin Prescription

Study objective: The optimal timing to begin stroke prevention therapy in patients being discharged from an emergency department (ED) with atrial fibrillation is not known. We determined whether eligible patients who were provided with an ED prescription for oral anticoagulation had better rates of long-term anticoagulation use than eligible patients who were referred to their primary care provider for further care.

Methods: As part of a historical cohort study, in this planned substudy we abstracted data from patient charts with a primary diagnosis of atrial fibrillation from 24 EDs between April 1, 2008, and March 31, 2009. In the current study, discharged patients aged 65 years and older who had a CHADS2 score greater than or equal to 2 and a HAS-BLED score less than 3, with no history of falls and who were not receiving oral anticoagulation when they presented to the ED, were included. We compared the frequency of warfarin use at 6 months and 1 year after ED discharge for patients who were given a prescription for warfarin before they left the ED to those who were not.

Results: Among 137 qualifying patients, 33 (24.1%) were provided with a warfarin prescription before discharge from the ED. At 6 months, 25 of the 33 were still receiving warfarin, compared with 34 of 104 among the patients who were not given an ED prescription (absolute difference, 43.1%; 95% confidence interval [CI] 23.8 to 57.2). At 1 year, 75.8% versus 35.6% (absolute difference, 40.2%; 95% CI 20.9 to 54.4) were receiving warfarin, respectively. Among the patients who filled a prescription for warfarin, the mean number of days from ED discharge until a warfarin prescription was filled was 6.0 (SD 21.3) for patients who were provided with an ED prescription compared with 205 (SD 377) for those who were not.

Conclusion: Among ED patients who met criteria for guideline-recommended use of stroke prevention therapy, those who received an initial prescription in the ED had a higher frequency of long-term warfarin use than those for whom the decision to initiate therapy was referred to another care provider.