Abstract 282: Dabigatran Etexilate is Associated with Shorter Hospital Length of Stay Compared to Warfarin in Patients with Nonvalvular Atrial Fibrillation

Background: Warfarin and dabigatran etexilate (DE) are oral anticoagulants used to reduce the risk of stroke among patients with nonvalvular atrial fibrillation (NVAF). This study examined whether hospital length of stay (LOS) differed for the two therapies. Methods: LOS was evaluated for patients hospitalized with a primary or secondary discharge diagnosis of atrial fibrillation (AF) between 1/1-3/31/2011, with DE or warfarin administered during hospitalization, and excluding patients with a valvular procedure. Patients were identified from a hospital Charge Detail Masters database, consisting of 184 hospitals. Differences in LOS by therapy were estimated using propensity score-matched samples selected by nearest neighbor matching within a caliper of 0.20 standard deviations of the logit, without replacement and a 2:1 match. Covariates used to estimate the propensity score included age, gender, CHADS2score, comorbid conditions and hospital attributes. LOS was also analyzed in patient subgroups identified by use of specific bridging agents (low-molecular weight heparin, unfractionated heparin, combination of the heparins, or no bridging agent) and a subset categorized as newly diagnosed NVAF. Results: Matched samples included 2,372 warfarin and 1,186 DE patients selected from 19,725 warfarin and 1,190 DE patients. Covariates used for the propensity score were not significantly different in the matched samples. LOS was 1.06 days shorter for DE compared to warfarin (DE: 6.16 days vs. warfarin: 7.22 days, p<0.01). In the 4 subgroups identified by choice of bridging agent, LOS was significantly shorter for DE in 3 (0.8 to 1.4 days, p<0.011), but not the fourth (0.9 day, p=0.3). In the subset of newly diagnosed NVAF, LOS was not significantly shorter for DE when AF was the primary discharge diagnosis (0.5 day, p=0.15), but was 2.47 days shorter for DE patients (p<0.01) when AF was a secondary discharge diagnosis. Limitations of the study were small sample sizes in some subgroups and potential of residual confounding. Conclusions: Among hospitalized patients with NVAF receiving an oral anticoagualant, patients receiving DE had a shorter length of stay compared to patients receiving warfarin.