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Professional organizations recommend that antimicrobial stewardship programs measure their antimicrobial drug use and the clinical outcomes of interventions that change drug use.
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The recommended metric to quantify inpatient antimicrobial drug use in the United States is days of therapy per 1000 patient-days. Additional metrics are being evaluated.
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Benchmarking risk adjusted antibiotic use across multiple hospitals is possible; research is needed to determine if stewardship programs will use the
Antimicrobial Use Metrics and Benchmarking to Improve Stewardship Outcomes: Methodology, Opportunities, and Challenges
Section snippets
Key points
Introduction: nature of the problem
All antimicrobial stewardship programs (ASPs) have a common goal: to improve the quality of antibiotic prescribing. It follows that a successful ASP must be able to accomplish 2 tasks: (1) measure antimicrobial usage to know if an intervention was effective in changing antimicrobial use and (2) measure an outcome related to the change in use. Nearly all position papers from professional organizations and expert commentaries support these 2 tasks (Box 1).
Outcomes of ASPs historically focused on
Process Versus Outcomes
Box 1 includes frequent reference to elements from the Donabedian model of health care quality measurements, specifically the terms process and outcomes measures.21 Wikipedia states, “…the Donabedian Model continues to be the dominant paradigm for assessing the quality of health care. According to the model, information about quality of care can be drawn from 3 categories: structure, process, and outcomes.”21 Applying this model to ASPs, structure is the presence or absence of an ASP, process
Interventions to reduce antimicrobial use
Although measurement of antibiotic use is a process measure, antibiotics are unlike other drugs because excessive use compromises their usefulness; improved antibiotic use after an ASP intervention remains a critical metric to ensure future availability of this valuable medical resource (see Box 1). Because all ASPs attempt to change antibiotic use, the common measures of antimicrobial use are summarized first, followed by the role of benchmarking as a tool to improve use.
Areas in which more work is needed
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Most multivariable regression models applied to benchmarking were developed in Europe, where DDD/1000PDs was the outcome metric.39, 41 Although the DDD methodology does measure antibiotic use in a facility, it is severely compromised by a major confounder: the DDD value for total antibiotic use is also affected by the hospital’s formulary composition.37 Consequently, the DOT/1000 PD metric is becoming the standard measure for quantifying aggregate antimicrobial use in the United States,
Areas in which more work is needed
Platt’s comments about benchmarking health care–associated infections are also relevant to antimicrobial use: “We have made great progress since the CDC’s landmark demonstrations of the utility of SSI surveillance to identify ways that hospitals can reduce their infection rates. It is important to do the new research needed to move surveillance from a research tool to one that can be widely used to support improved care.”36 The following are some of the research questions to be addressed so
Economic
Economic outcomes remain important to most programs and are the driving force supporting many programs. There have been many previous reviews of the economic benefits of stewardship; a common theme is that the cost savings of a new ASP are often dramatic in the first few years, but that savings plateau and may obscure a persistent economic benefit.11, 13, 55 The economic impact after discontinuation of an established program was recently reported by Standiford and colleagues13 from the
Summary
Measurement of inpatient antimicrobial use before and after ASP interventions and the associated outcomes should be core activities of a successful program. Measurement of antimicrobial drug use is becoming standardized and feasible in most institutions. To ensure the future of stewardship programs, outcomes from interventions must progress from economic measures to measures that document improved clinical outcomes, including lower rates of bacterial resistance. Benchmarking of antimicrobial
Acknowledgments
The authors wish to thank Drs Sam Hohmann and Saloni Kapur at the University HealthSystem Consortium (UHC) for their continued support by providing the data for Fig. 1. We also are grateful to the UHC hospital stewardship program personnel, who have been supportive of the research described in this review.
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Funding Support: The authors have nothing to disclose.
Conflicts of Interest: The authors have nothing to disclose.