A cost-analysis model for anticoagulant treatment in the hospital setting

Figures & data

Table 1. Summary of pivotal trials of rivaroxaban by population.

Population	Trial	Treatment comparator	n*	Age, years†	Male, n (%)
NVAF	ROCKET AF	Rivaroxaban	7131	73 (65–78)	4300 (60)
		Warfarin	7133	73 (65–78)	4301 (60)
DVT	EINSTEIN DVT	Rivaroxaban	1731	56 (16)	993 (57)
		Enoxaparin + Warfarin	1718	56 (16)	967 (56)
PE	EINSTEIN PE	Rivaroxaban	2419	58 (7)	1309 (54)
		Enoxaparin + Warfarin	2413	58 (7)	1247 (52)
Knee	RECORD3	Rivaroxaban	1220	68 (28–91)	363 (30)
		Enoxaparin	1239	68 (30–90)	418 (34)
Hip	RECORD1	Rivaroxaban	2209	63 (18–91)	989 (45)
		Enoxaparin	2224	63 (18–93)	982 (44)
	RECORD2	Rivaroxaban	1228	61 (18–93)	561 (46)
		Enoxaparin	1229	62 (19–93)	578 (47)

*The sample counts for the ROCKET AF, EINSTEIN DVT, and PE trials were based on the intention-to-treat population, while the RECORD1-3 trials were based on the safety population.

†The ROCKET AF trial reported the median age with interquartile range, EINSTEIN DVT, and PE reported mean age with SD, and the RECORD1-3 reported mean age with range.

Table 2. Population distribution.

	Population
	NVAF	DVT	PE	Knee	Hip
ICD-9 code	427.31	451.11–451.19, 451.2, 453.40–453.42, 453.8–453.89, 453.9	415.11–415.19	81.54	81.51
Inputs from HCUP21
Number of admissions	422,933	160,363	179,160	656,635	301,798
% as overall number of admissions	24.6%	9.3%	10.4%	38.2%	17.5%
Mean cost per inpatient stay (2010 USD)	$8474	$8304	$11,083	$15,924	$16,596
Mean length of stay (days)	3.5	4.8	5.4	3.3	3.4
Economic model inputs
Number of admissions in the assumed cohort	403	152	170	625	286
Mean cost per day (2010 USD)	$2421	$1730	$2052	$4825	$4881

Table 3. Model inputs.

	Population
	NVAF	DVT	PE	Knee	Hip	Source
Resource utilization
Length of stay
Rivaroxaban	3.0	5.0	6.0	3.0	3.0	Laliberte et al.15; Van Bellen et al.16; HCUPnet21
Warfarin	4.0	–	–	–	–	Laliberte et al.15
Enoxaparin	–	–	–	3.0	3.0	HCUPnet21
Enoxaparin/warfarin	–	8.0	7.0	–	–	EINSTEIN DVT/PE2,3
Frequency of PT/INR tests performed per day	1.0	1.0	1.0	–	–	Assumption
Unit costs
Anticoagulant treatment cost
Rivaroxaban (20/15/10 mg QD)	$8.84	–	–	$8.84	$8.84	AnalySource13
Rivaroxaban (2.5/5/15 mg BID)	–	$17.68	$17.68	–	–	AnalySource13
Generic enoxaparin (1 mg/kg BID)	–	$88.00	$88.00	–	–	RED BOOK12; assume 80 kg weight
Generic enoxaparin (40 mg DQ)	–	–	–	$22.00	$22.00	RED BOOK12
Generic warfarin (per day)	$0.12	$0.12	$0.12	–	–	RED BOOK12
Monitoring cost
PT/INR monitoring	$5.56	$5.56	$5.56	–	–	Center for Medicare and Medicaid Services14
Inpatient stay cost
Cost per day (2012 USD)	$2586	$1848	$2192	$5155	$5214	HCUPnet21

Table 4. Economic model of inpatient hospital cost (2012 USD) per patient.

	Population
Cost savings analysis ($)	NVAF	DVT	PE	Knee	Hip	Overall*
Total costs under other agents	10,368	15,533	16,003	15,530	15,708	14,340
Total costs under rivaroxaban	7785	9328	13,260	15,490	15,669	12,821
Potential savings	2582	6205	2742	39	39	1520
Savings as a percentage of total costs under other agents	24.9%	39.9%	17.1%	0.3%	0.3%	10.6%

*The overall potential cost savings per patient is a weighted average of the five populations based on the HCUP hospital admission distribution from Table 2.

Table 5. Simulated potential cost savings (2012 USD) per patient.

	Population
	NVAF	DVT	PE	Knee	Hip	Overall*
Total	2582	6205	2742	39	39	1520
Anticoagulant treatment	−26†	617	511	39	39	126
Monitoring	22	44	39	0	0	14
Inpatient stay	2586	5544	2192	0	0	1380
Administration/ education/other	0	0	0	0	0	0

*The overall potential cost savings per patient is a weighted average of the five populations based on the HCUP hospital admission distribution from Table 2.

†A negative value indicates higher costs per patient for rivaroxaban.

Table 6. One-way sensitivity analyses—simulated potential cost savings per patient by varying input parameters.

	Parameter value		Cost savings under rivaroxaban ($)
Parameters	Lower bound	Upper bound	Lower bound	Upper bound
LOS difference (days)*	0	NVAF: 1, DVT: 3, PE: 4	102	2233
Inpatient stay cost ($)
All populations	–	–	830	2209
NVAF	1293	3879	1201	1838
DVT	924	2772	1262	1777
PE	1096	3289	1406	1634
Rivaroxaban usage rate	50%	100%	760	1520

*For the lower bound cost savings, no difference in LOS between rivaroxaban and comparators for each population was assumed. For the upper bound cost savings, the difference in the 75^th percentile LOS between rivaroxaban and comparators for NVAF, DVT, and PE was applied.

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