Interventions to Regulate Ordering of Serum Magnesium Levels: Report of an Unintended Consequence of Decision Support
- Affiliations of the authors: Departments of Biomedical Informatics (STR, RAM), Biostatistics (DWB), and Internal Medicine (DWB, EGN), School of Nursing (STR), Vanderbilt University, Nashville, TN; Department of Family Medicine, Riverside Regional Medical Center, Newport News, VA (K-WC); Department of Computer Science, Tennessee Technological University, Cookeville, TN (DAT)
- Correspondence and reprints: S. Trent Rosenbloom, MD, MPH, Eskind Biomedical Library, Room 440, 2209 Garland Avenue, Nashville, TN 37232-8340; e-mail: <trent.rosenbloom{at}vanderbilt.edu>
- Received 11 February 2005
- Accepted 27 April 2005
Abstract
Background Unintended consequences of computerized patient care system interventions may increase resource use, foster clinical errors, and reduce users' confidence.
Objective To evaluate three successive interventions designed to reduce serum magnesium test ordering through a care provider order entry system (CPOE). The second, modeled after a previously successful intervention, caused paradoxical increases in magnesium test ordering rates.
Design A time-series analysis modeled weekly rates of magnesium test ordering, underlying trends, the impact of the three successive interventions, and the impact of potential covariates. The first intervention exhorted users to discontinue unnecessary tests recurring more than 72 hours into the future. The second displayed recent magnesium, calcium, and phosphorus test results, limited testing to one test instance per order, and provided education regarding appropriate indications for testing. The third targeted only magnesium ordering, displayed recent results, limited testing to one instance per order, summarized indications for testing, and required users to select an indication.
Participants Clinicians at Vanderbilt University Hospital, a 609-bed academic inpatient tertiary care facility, from 1998 through 2003.
Measurements Weekly rates of new serum magnesium test orders, instances, and results.
Results At baseline, there were 539 magnesium tests ordered per week. This decreased to 380 (p = 0.001) per week after the first intervention, increased to 491 per week (p < 0.001) after the second, and decreased to 276 per week (p < 0.001) after the third.
Conclusion A clinical decision support intervention intended to regulate testing increased test order rates as an unintended result of decision support. CPOE implementers must carefully design resource-related interventions and monitor their impact over time.
Footnotes
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The project was supported by United States National Library of Medicine Grants (5 T15 LM007450-02 and 5 R01 LM 06226), the Vanderbilt General Clinical Research Center (M01-RR00095), the Vanderbilt Physician Scientist Development Program, and Vanderbilt University Medical Center Funds.
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The WizOrder Care Provider Order Entry (CPOE) system described in this manuscript was developed by Vanderbilt University Medical Center faculty and staff within the School of Medicine and Informatics Center beginning in 1994. In May 2001, Vanderbilt University licensed the product to a commercial vendor, who is modifying the software. The system as described represents the Vanderbilt noncommercialized software code. Dr. Rosenbloom, the manuscript's lead author, has been paid by the commercial vendor in the past to demonstrate to potential clients the noncommercialized product. Drs. Miller and Talbert have been recognized by Vanderbilt as contributing to the authorship of the WizOrder software and have received and will continue to receive royalties from Vanderbilt under the University's intellectual property policies. While these involvements could potentially be viewed as a conflict of interest with respect to the submitted manuscript, the authors have taken a number of concerted steps to avoid an actual conflict, specifically by including additional authors and a statistician not involved in development or commercialization of the CPOE system.
