OBJECTIVES: While discontinuation of warfarin therapy for stroke prevention is common in patients with atrial fibrillation, little is known about health outcomes associated with warfarin discontinuation. This study compared health care utilization/costs between patients with non-valvular atrial fibrillation who were persistent with warfarin therapy (WP patients) and those who discontinued warfarin therapy (WD patients) in the US usual clinical practice setting.

METHODS: A retrospective observational study was conducted among patients (≥18 years of age) with non-valvular AF who were on warfarin in the US MarketScan Database (01/2008-06/2012). Warfarin discontinuation was identified by a gap >45 days in warfarin prescriptions within one year of warfarin initiation. A propensity score method was used to match WP patients and WD patients to produce compatible index dates. Patients’ follow-up started from the discontinuation date for WD patients and after the same duration of warfarin therapy for matched WP patients. Patients were followed for up to one year to determine the annualized number and costs of health care utilization. To adjust for patient characteristics, multivariate analyses were conducted.

RESULTS:  27,000 matched patients were included for the analysis. Mean follow-up duration was 264 days for WD and 339 days for WP groups. Compared with WP patients, WD patients were more likely to be hospitalized (Mean: 0.51 vs. 0.37, P<0.001) and to visit ER (Mean: 1.14 vs. 1.01, P<0.001). The total annualized costs in WD group was significantly higher than WP group ($24,701.2 vs. $19,836.3, P<0.001). Hospitalization accounted for 34.57% of total costs. After adjusting for patient characteristics, the patterns of differences between the two groups remain the same. CONCLUSIONS: Warfarin discontinuation is associated with higher number of hospitalizations and ER visits and higher total health care costs than warfarin persistence. Future studies should examine strategies to improve patient persistence with anticoagulants and lower total health care costs.