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

Abstract

Background:

The Efficacy of Vasopressin Antagonism in Heart Failure Outcome Study with Tolvaptan (EVEREST) trial showed that tolvaptan use improved heart failure (HF) signs and symptoms without serious adverse events.

Objective:

To evaluate the potential cost savings associated with tolvaptan usage among hospitalized hyponatremic HF patients.

Methods:

The Healthcare Cost and Utilization Project (HCUP) 2008 Nationwide Inpatient Sample (NIS) database was used to estimate hospital cost and length of stay (LOS), for diagnosis-related group (DRG) hospitalizations of adult (age ≥18 years) HF patients with complications and comorbidities or major complications and comorbidities. EVEREST trial data for patients with hyponatremia were used to estimate tolvaptan-associated LOS reductions. A cost offset model was constructed to evaluate the impact of tolvaptan on hospital cost and LOS, with univariate and multivariate Monte Carlo sensitivity analyses.

Results:

Tolvaptan use among hyponatremic EVEREST trial HF patients was associated with shorter hospital LOS than placebo patients (9.72 vs 11.44 days, respectively); 688,336 hospitalizations for HF DRGs were identified from the HCUP NIS database, with a mean LOS of 5.4 days and mean total hospital costs of $8415. Using an inpatient tolvaptan treatment duration of 4 days with a wholesale acquisition cost of $250 per day, the cost offset model estimated a LOS reduction among HF hospitalizations of 0.81 days and an estimated total cost saving of $265 per admission. Univariate and multivariate sensitivity analysis demonstrated that cost reduction associated with tolvaptan usage is consistent among variations of model variables.

Conclusions:

The estimated LOS reduction and cost savings projected by the cost offset model suggest a clinical and economic benefit to tolvaptan use in hyponatremic HF patients.

Study Limitations:

The EVEREST trial data may not generalize well to the US population. Clinical trial patient profiles and relative LOS reductions may not be applicable to real-world patient populations.

Keywords::

• HCUP
• NIS
• Cost-offset model
• Heart failure
• Hyponatremia
• Tolvaptan

Transparency

Declaration of funding

This research was supported by Otsuka America Pharmaceutical, Inc., Princeton, NJ.

Declaration of financial/other relationships

J.D. and J.C. are consultants for and have received honoraria from Otsuka. J.L. is an employee of Novosys Health, which has received research funds from Otsuka America Pharmaceutical. R.C. is an employee of Otsuka America Pharmaceutical, Inc. S.K. was an employee of Otsuka America Pharmaceutical, Inc. at the time of the study.

Acknowledgments

The authors would like to acknowledge Tina Wright from Otsuka America Pharmaceutical, Inc. for her critical review of the manuscript. No other assistance in the preparation of this article is to be declared. Various aspects of the study results have been presented at the International Society for Pharmacoeconomics and Outcomes Research (ISPOR) 16th Annual International Meeting in Baltimore, MD on May 21st to May 25th, 2011 and presented at the American College of Chest Physicians (ACCP) 2011 Conference as an Oral Presentation.