Authors (including presenting author) :
Fung A (1)(2), Ng V(2)
Affiliation :
(1)School of Pharmacy, Faculty of Medicine, the Chinese University of Hong Kong, Hong Kong SAR, China (2)Pharmacy Department, Princess Margaret Hospital, Hong Kong SAR, China
Introduction :
For decades, the inpatient treatment of venous thromboembolism (VTE) has been warfarin bridging with low molecular weight heparin. Rivaroxaban, a new oral anticoagulant, has demonstrated non-inferiority to warfarin in VTE treatment with easier initiation, less bleeding risks and less monitoring. However, there is limited local data to compare the hospital length of stay (LOS) and related cost of rivaroxaban versus warfarin.
Objectives :
The primary objectives were the hospital LOS and hospitalization cost for the first VTE event. The secondary objectives were the direct medical cost and clinical outcomes for one year following VTE event. Anticoagulation control for warfarin patients was also evaluated.
Methodology :
In this retrospective observational study, data from VTE patients admitted at Princess Margaret Hospital from March 2012 to Feb 2017 who were discharged with either rivaroxaban or warfarin were collected. Direct medical cost including hospitalization, clinic visits, laboratory tests, diagnostic procedures and medication were calculated for the index VTE hospitalization and one-year post index period. Consultation notes were also reviewed to collect any documentation of recurrent VTE and bleeding events.
Result & Outcome :
A total of 91 rivaroxaban patients and 90 warfarin patients were included in this study. Mean (±SD) LOS was 4.8±2.7 days for patients taking rivaroxaban and 8.0±3.0 days for patients taking warfarin. Patients initiated on rivaroxaban incurred significantly lower median hospitalization cost. ($22,423 versus $41,969, p<0.001) Rivaroxaban treatment was a negative predictor of high-cost hospitalization. (OR=0.284; 95% CI 0.122, 0.658) Pulmonary embolism was the positive predictor of high-cost hospitalization. (OR 3.814; 95% CI 1.681-8.654) No significant difference was observed between treatment groups for recurrent VTE and bleeding for one-year post index period. The median direct medical cost for one-year post VTE event was significantly lower in rivaroxaban cohort than warfarin cohort. ($8,798 vs. $11,413, p<0.001) The average Therapeutic Time in Range (TTR) in warfarin cohort was 49.1%. Only one-third of the patients could achieve TTR of at least 65%. The mean direct medical cost was higher in patients with TTR below 65% than patients attaining 65% or above. Rivaroxaban was associated with significantly shorter hospital LOS, lower hospitalization cost and lower direct medical cost for one-year post index compared to warfarin. Anticoagulation control was not adequate in warfarin cohort and poor TTR control was associated with higher treatment costs. Rivaroxaban may be a better alternative to warfarin for VTE treatment, owing to its cost saving benefit.
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