Economic Impact of Venous Thromboembolism After Hip and Knee Arthroplasty

Potential Impact of Rivaroxaban

Richard J Friedman; Nishan Sengupta; Michael Lees

Disclosures

Expert Rev Pharmacoeconomics Outcomes Res. 2011;11(3):299-306. 

In This Article

Potential Economic Impact of Rivaroxaban Use

Potential savings associated with oral rivaroxaban could be based on reductions in the incidence of symptomatic venous thromboembolic events and reduced administration and monitoring costs.

Economic decision models have been developed based on the efficacy and safety parameters from individual RECORD studies.[55] Separate models were required because of the different treatment durations and doses of enoxaparin. The models followed patients for up to 1 year after THA or TKA surgery. The clinical efficacy (reductions in the incidence of DVT, nonfatal PE and symptomatic VTE) and safety profiles of both drugs were taken from the RECORD studies[43–46] and the incidence of symptomatic VTE up to 90 days after surgery was extrapolated based on epidemiological data.[56] This extrapolation allowed for the proportion of untreated asymptomatic events becoming symptomatic after the end of the study period. The incidence of recurrent VTE and post-thrombotic syndrome beyond this period was based on clinical data derived from a prospective long-term follow-up study.[57] Treatment costs for symptomatic VTE and major bleeding were taken from published data on managed care in the USA.[35,58] For costing purposes, the duration of hospitalization for THA (3 days) and TKA (4 days) was obtained from GLORY.[23] Because major bleeding requires physician visits and possibly attendance at an emergency room or hospitalization, which are expensive, the economic models only included costs associated with major bleeding (Table 1). In the analyses, it was conservatively assumed that no incremental nurse time or home visit costs were associated with sc. enoxaparin injection. The duration of prophylaxis with rivaroxaban was 35 days for THA patients and 14 days for TKA patients. Because rivaroxaban is not available in the USA, the analysis made the assumption of similar daily drug acquisition costs to enoxaparin 40 mg q.d. (as found in Canada).

The 1-year analysis based on RECORD1 showed that rivaroxaban resulted in an average cost saving of US$82 per patient and a reduction of six symptomatic events per 1000 patients undergoing THA. A similar analysis based on RECORD3 demonstrated that rivaroxaban resulted in an average cost saving of US$284 per patient and a reduction of 18 symptomatic events per 1000 patients undergoing TKA. In RECORD4, in which the enoxaparin regimen was 30 mg b.i.d., rivaroxaban was associated with an average cost saving of US$291 per patient and a reduction of two symptomatic events per 1000 patients undergoing TKA.[55] These improvements were primarily driven by the reduced costs of hospitalization for symptomatic events (Table 2).

If we apply these cost and event reductions to the THA and TKA figures from 2005,[1] the use of rivaroxaban would save US$23,370,000 (285,000 × US$82) and reduce the number of symptomatic events after THA by 1710 per year compared with the use of enoxaparin. Similarly, after TKA, the use of rivaroxaban would save US$149,055,000 (523,000 × US$285) and reduce the number of symptomatic events by 9414 per year compared with enoxaparin 40 mg q.d. and US$152,193,000 (523,000 × US$291), and 8368 symptomatic events per year compared with enoxaparin 30 mg b.i.d.

However, these analyses were very conservative and the use of an oral agent could be even more cost effective than these estimates. Published data suggest that home nursing visits for prophylaxis after hospital discharge cost US$100 for a course of enoxaparin.[59]

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