Evaluation of costs associated with tolvaptan-mediated length-of-stay reduction among heart failure patients with hyponatremia in the US, based on the EVEREST trial

Figures & data

Table 1.  EVEREST Trial—post-hoc analysis of LOS19.

Intervention	n	Adjusted* mean LOS (days)	Mean LOS difference	p-value
Tolvaptan (30 mg)	225	9.72	−1.72	= 0.06
Standard of care (placebo)	216	11.44

Table 2.  Resource usage of HCUP HF patients.

Adult hospital admissions			Per admission (mean)				Aggregate		Hospital cost per day
Age group	Count	% of total	LOS, days	Charges	Costs	LOS, days	Charge	Cost
Total	688,336	100.0%	5.4	$26,603	$8415	3,696,702	$18,312,076,596	$5,792,440,664	$1567
18–44	26,738	3.88%	4.5	$25,339	$7999	120,427	$677,524,754	$213,883,711	$1776
45–64	143,684	20.87%	5.1	$26,467	$8481	728,555	$3,802,865,852	$1,218,550,131	$1673
65–84	342,045	49.69%	5.5	$27,139	$8587	1,870,125	$9,282,922,941	$2,937,299,503	$1571
85+	175,869	25.55%	5.6	$25,865	$8090	977,595	$4,548,763,049	$1,422,707,319	$1455

The study population, consisting of adult patients hospitalized for HF, was extracted from the HCUP 2008 NIS database based on the HF-related DRGs 291 and 292. The resource usage reported includes the mean and aggregate length of stay (LOS, days), hospital charges, and hospital costs, stratified by patient age.

*Costs are derived from total hospital charges using cost-to-charge ratios based on hospital accounting reports from the Centers for Medicare and Medicaid Services (CMS). Costs will tend to reflect the actual costs to produce hospital services, while charges represent what the hospital billed for the care.

Table 3.  Resource reduction due to tolvaptan usage (per admission).

Type of resource	EVEREST trial				Cost offset model
	Placebo	Tolvaptan	Difference^a	Relative difference^b	Resource reduction^c
Length of stay (days)	11.44	9.72	1.72	15.0%	0.81
Total hospital cost ($)	$17,926	$15,230	$2,695	15.0%	$1,265

^aPlacebo − Tolvaptan.

^bDifference/placebo.

^cMean per admission LOS/Cost for HCUP HF patients × relative difference.

The tolvaptan-associated reduction in LOS was derived from a post-hoc analysis of the EVEREST trial. The total hospital costs reported reflect the estimated hospital costs for HCUP HF patients with a LOS similar to that of EVEREST trial patients. The 15% tolvaptan-associated relative reduction in LOS among EVEREST trial patients was used to estimate the potential LOS and total hospital cost reductions due to hypothesized tolvaptan usage among the HCUP HF patient population.

Table 4.  Overall resource reduction due to tolvaptan usage.

Type of resource	Reduction per admission	Cost of tolvaptan use	Total cost offset^a	Number of HCUP HN HF patients	Total cost offset among HCUP HN HF population^b
Total Hospital Cost ($)	$1265.21	$1000	$265	79,159	$20,993,820
Length of stay (days)	0.81	–	–	79,159	63,917

^aReduction per admission − Cost of tolvaptan use.

^bTotal cost offset × Number of HCUP HN HF patients.

The total cost offset associated with tolvaptan usage among HCUP HF patients was defined as the difference between the tolvaptan-related cost reduction per admission (Table 3) and the cost of tolvaptan use during hospitalization (duration of tolvaptan use (4 days) × wholesale acquisition cost of tolvaptan ($250)). The number of HF patients with hyponatremia (HN) was estimated by applying a hyponatremia incidence rate of 11.5% to the HCUP HF study population. The total reduction in LOS associated with tolvaptan usage among HCUP HF patients was estimated by applying the derived tolvaptan-related LOS reduction (Table 3) to the estimated number of hyponatremic (HN) HCUP HF patients.

Figure 1.  Univariate sensitivity analysis. Individual model parameters were allowed to vary ±20%. (a) Total cost offset reduction, (b) LOS reduction.

Figure 2.  Multivariate sensitivity analysis. Each variable used for the cost offset or LOS univariate sensitivity analysis was allowed to vary simultaneously for 10,000 cycles, with the value of the corresponding variables taken randomly from a normal distribution with a coefficient of variation of 0.20 for each cycle. (a) Total cost offset, (b) LOS reduction.

Cyr PL, Slawsky KA, Olchanski N, et al. Effect of serum sodium concentration and tolvaptan treatment on length of hospitalization in patients with heart failure. Am J Health Syst Pharm 2011;68:328-33

 PubMed Web of Science ®Google Scholar