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Cost Analysis of the STONE Randomized Trial: Can Health Care Costs be Reduced One Test at a Time?

Melnikow, Joy MD, MPH; Xing, Guibo PhD; Cox, Ginger RHIT, CCS; Leigh, Paul PhD; Mills, Lisa MD; Miglioretti, Diana L. PhD; Moghadassi, Michelle MPH; Smith-Bindman, Rebecca MD

doi: 10.1097/MLR.0000000000000487
Original Articles

Background: Decreasing the use of high-cost tests may reduce health care costs.

Objective: To compare costs of care for patients presenting to the emergency department (ED) with suspected kidney stones randomized to 1 of 3 initial imaging tests.

Research Design: Patients were randomized to point-of-care ultrasound (POC US, least costly), radiology ultrasound (RAD US), or computed tomography (CT, most costly). Subsequent testing and treatment were the choice of the treating physician.

Subjects: A total of 2759 patients at 15 EDs were randomized to POC US (n=908), RAD US, (n=893), or CT (n=958). Mean age was 40.4 years; 51.8% were male.

Measures: All medical care documented in the trial database in the 7 days following enrollment was abstracted and coded to estimate costs using national average 2012 Medicare reimbursements. Costs for initial ED care and total 7-day costs were compared using nonparametric bootstrap to account for clustering of patients within medical centers.

Results: Initial ED visit costs were modestly lower for patients assigned to RAD US: $423 ($411, $434) compared with patients assigned to CT: $448 ($438, $459) (P<0.0001). Total costs were not significantly different between groups: $1014 ($912, $1129) for POC US, $970 ($878, $1078) for RAD US, and $959 ($870, $1044) for CT. Hospital admissions contributed over 50% of total costs, though only 11% of patients were admitted. Mean total costs (and admission rates) varied substantially by site from $749 to $1239.

Conclusions: Assignment to a less costly test had no impact on overall health care costs for ED patients. System-level interventions addressing variation in admission rates from the ED might have greater impact on costs.

*Center for Healthcare Policy and Research

Department of Public Health Sciences

Department of Emergency Medicine, University of California, Davis, Sacramento

§Department of Radiology and Biomedical Imaging

Radiology Outcomes Research Laboratory

Department of Epidemiology, Biostatistics and the Philip R. Lee Institute for Health Policy Studies, University of California, San Francisco, San Francisco, CA

Supported by the American Recovery and Reinvestment Act (ARRA) of 2009 through the Agency for Healthcare Research and Quality (AHRQ) Grant #R01HS019312.

AHRQ had no role in the design, data collection, analysis, or interpretation of the study data. The content of this manuscript is solely the responsibility of the authors and does not necessarily represent the views of the Agency for Healthcare Research and Quality.

The authors declare no conflict of interest.

Reprints: Joy Melnikow, MD, MPH, Center for Healthcare Policy and Research, University of California, Davis, 2103 Stockton Blvd, Sacramento, CA 95817. E-mail:

Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.