Objective: This study evaluated safety and effectiveness outcomes among non-valvular atrial fibrillation (NVAF) patients treated with dabigatran or warfarin using an administrative claims database.
Methods: NVAF patients with no oral anticoagulant (OAC) use prior to their first prescription claim for FDA-approved dosages of either dabigatran or warfarin between 01-Oct-2010 and 30-Apr-2014 were identified. Patients aged 18-89 years with medical and pharmacy benefits were selected. Patients with valvular heart disease, transient causes of AF, or hyperthyroidism at baseline were excluded. Patients were followed until discontinuation of index medication, OAC switch, disenrollment, death, or end of observation period. Dabigatran and warfarin patients were propensity score matched (PSM, 1:2) using baseline demographics and clinical characteristics. Outcomes were measured either using diagnosis codes from all service lines in medical claims (Method A) or using an algorithm to derive principal diagnosis (Method B). Outcome measurements using Method B are comparable to prior database studies that used principal diagnosis. Safety and effectiveness outcomes of the matched cohorts were assessed using Cox-proportional hazards models.
Results: A total of 7,245 dabigatran (1,016 receiving 75 mg and 6,229 receiving 150 mg) and 14,490 warfarin patients were analyzed (Table 1). The patients were 56% male, with a mean age of 74 years, mean CHADS2 stroke risk score of 2.2, and mean HAS-BLED bleeding risk score of 3.4. Based on the hazard ratios, lower risks for primary (major bleeding) and secondary (hemorrhagic stroke, major intracranial bleeding, major extracranial bleeding [major urogenital and other bleeding], and death) outcomes were observed in the PSM dabigatran cohort compared to warfarin cohort (Method B).
Conclusions: These results are largely consistent with findings from previous studies that support the benefits of dabigatran therapy in NVAF patients.