Background: Compared to warfarin, the new target-specific oral anticoagulant rivaroxaban may have advantages in treating patients with venous thromboembolism because injectable bridging therapy and routine laboratory monitoring are not required. The objective of this study was to compare the rate of hospitalization in patients treated with rivaroxaban after its introduction with what it would have been before the introduction of rivaroxaban.
Methods: A retrospective claims analysis was conducted using the MarketScan Hospital Drug Database from 01/2011 to 12/2013. Adult patients with a primary diagnosis of DVT treated with rivaroxaban or low-molecular-weight heparin (LMWH) bridged to warfarin during the first day of an evaluation at a hospital were identified. Based on propensity-score methods historical LMWH/warfarin patients (i.e., patients who received LMWH/warfarin before the approval of rivaroxaban) were matched 4:1 to rivaroxaban patients, and the rates of hospitalization were compared. Current rivaroxaban patients were not matched with current warfarin patients because the objective was to compare the rate of hospitalization as an intervention after rivaroxaban became available to what it would have been before it became available. Furthermore, additional comparisons were conducted among different populations of current and historical LMWH/warfarin patients to assess the change in practice patterns over time (i.e., the time trend in hospital admissions). Comparisons between rivaroxaban and historical LMWH/warfarin cohorts were assessed using rate ratios (RRs) adjusting for the time trend in hospital admissions. All-cause hospitalization costs were also reported and compared between rivaroxaban and historical LMWH/warfarin cohorts.
Results: All rivaroxaban-treated patients (N=134) in the database were well-matched with 4 historical LMWH/warfarin-treated patients (N=536). The mean age of both cohorts was 62 years and approximately 50% of patients were female. Among the rivaroxaban cohort, 60% of patients were admitted to hospital, compared to 82% of historical patients treated with LMWH/warfarin in the matched-cohort. The difference was statistically significant and corresponded to a 27% reduction in hospital admissions (RR [95%CI]: 0.73 [0.62-0.83]; p-value<.001). Hospital admission rates adjusted for time trend analyses also led to similar results. The corresponding hospitalization costs were also significantly lower for rivaroxaban compared to historical LMWH/warfarin patients ($5,257 vs. $6,698; cost difference=$1,441, p-value=0.002).
Conclusions: The availability of rivaroxaban significantly reduced the hospitalization rate in patients with DVT treated with rivaroxaban compared to what it would have been if only LMWH/warfarin were available.