Comparison of hospital length of stay of acute ischemic stroke patients with non-valvular atrial fibrillation started on rivaroxaban or warfarin treatment during hospitalization
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Objective: To compare the hospital length of stay (LOS) between rivaroxaban and warfarin in hospitalized acute stroke patients with non-valvular atrial fibrillation (NVAF) in Japan.
Methods: This was a retrospective, observational study using a Japanese hospital claims database. Data of NVAF patients who were started on oral anticoagulant (OAC) treatment during hospitalization were extracted and LOS-OAC (period from the initiation of index oral anticoagulant therapy to the end of hospitalization or censoring date) and medical costs were compared between rivaroxaban and warfarin treatments. To compare LOS-OAC, a time-to-event analysis was performed using the Kaplan-Meier method. The analysis period was from April 2012 to December 2015.
Results: This study included 773 rivaroxaban users and 1,077 warfarin users. After the propensity score matching, 546 patients for each treatment constituted the matched cohorts. Although the rivaroxaban users had a similar LOS-OAC to warfarin users (median, 18 vs. 19 days, p = 0.657) in the matched cohorts, 3-days shorter LOS-OAC was observed in the rivaroxaban users (median, 17 vs. 20 days, p = 0.043) after IPTW adjustment. Subgroup analysis by severity of stroke after IPTW adjustment demonstrated that rivaroxaban users had a shorter LOS-OAC than warfarin users among patients with mild (median, 10 vs. 14 days) and moderate stroke severity (22 vs. 27 days), but not among those with severe stroke severity (26 vs. 25 days).
Limitations: It is not possible to say that only confounder was stroke severity and therefore other possible known and unknown confounders could not be ruled out.
Conclusions: The rivaroxaban users had a 3-day shorter LOS-OAC after IPTW-adjustment. Using rivaroxaban was associated with a 4 to 5 days shorter LOS-OAC than using warfarin in patients with mild or moderate stroke, though treatment selection did not have a large impact in patients with severe stroke.