Abstract 234: Comparison of Hospital Length of Stay and Costs between Non-valvular Atrial Fibrillation Patients Treated with Either Apixaban or Warfarin

Background: Patients with non-valvular atrial fibrillation (NVAF) have an increased risk of stroke and are often treated with oral anticoagulants (i.e. warfarin). However, apixaban, a novel oral anticoagulant (NOAC), has been shown to significantly reduce stroke risk and result in a significantly shorter hospital length of stay (LOS) compared to those treated with warfarin. Objectives: To compare LOS and hospitalization costs among real-world hospitalized NVAF patients treated with apixaban or warfarin. Evaluate the difference in costs among different patient characteristics, including LOS and CHADS2 score. Methods: Patients ≥18 years of age diagnosed with AF (ICD-9-CM code: 427.31) were identified from the Premier Perspective Claims Database (01JAN2009-31MAR2014). Patients were required to have 30 days of follow-up post-index hospitalization discharge. Patients with claims for mitral valvular heart disease, valve replacement procedures, pregnancy or other NOACs during the index hospitalization were excluded. Patients were classified into two cohorts (apixaban and warfarin) depending on treatment received during hospitalization. Demographic and clinical characteristics were collected 12 months prior to and during the NVAF index hospitalization. The two cohorts were 1:1 propensity score matched (PSM) on patient and hospital characteristics to compare hospital LOS (days) and index hospitalization costs. Additionally, costs were stratified by LOS and CHADS2 score. Results: Before matching, patients treated with warfarin were older and sicker compared to those treated with apixaban. After 1:1 PSM, 2,571 patients were matched in each cohort, and baseline characteristics were well-balanced. The mean CHADS2 score was 2.4 for both cohorts. The mean (standard deviation [SD], median) hospital LOS (p<0.001) was significantly shorter for patients prescribed apixaban (5.1 [5.7], 3 days) compared to warfarin (5.7 [5.3], 4 days). Patients treated with apixaban had significantly lower hospitalization costs compared to those prescribed warfarin ($11,115 vs. $13,483; p<0.001), specifically among patients with LOS ≤7 days (0-2 days: $4,909 vs. $5,780, p=0.006; 3-7 days: $9,430 vs. $10,289, p=0.007). The results were consistent when stratified by CHADS2 score; patients with CHADS2 0-1 ($9,761 vs. $13,418) and CHADS2≥2 ($11,607 vs. $13,506) treated with apixaban incurred significantly lower costs compared to those treated with warfarin (p<0.001). Conclusions: NVAF patients treated with apixaban had significantly shorter hospital LOS and lower index hospitalization costs compared to those treated with warfarin. Costs remained significantly lower for apixaban patients across all CHADS2 scores.