The report is a product of the VA/HSR Evidence Synthesis Program.

Antimicrobial Stewardship Strategies and Programs in the Outpatient Setting

Takeaway: Antimicrobial stewardship programs (ASPs) seek to improve antimicrobial prescribing practices, optimize patient outcomes, and reduce antimicrobial resistance. There has been substantial growth in the evidence base for antimicrobial stewardship in outpatient settings, but much of this evidence is observational and involved primarily audit and feedback with or without clinician and/or patient education. Audit and feedback, clinical decision support systems (embedded within electronic health records), or their combination did not consistently reduce overall or inappropriate antimicrobial prescribing in primary care or emergency room/urgent care settings. Limited evidence indicates that these strategies and their combination did not impact patient treatment outcomes and healthcare use. There remains an urgent need for effective strategies or multicomponent ASPs that can be implemented and sustained on a large scale in the outpatient setting.

Antimicrobial stewardship programs (ASPs) seek to improve antimicrobial prescribing practices, optimize patient outcomes, and reduce antimicrobial resistance. Growing antimicrobial resistance leaves patients with fewer antimicrobial options, leading to potentially increased drug toxicity and increased mortality. More than 80% of antimicrobial usage occurs in the outpatient setting, and nearly 30% of antibiotics prescribed in the outpatient setting may be inappropriate or unnecessary.

In response to a request from the VA National Antimicrobial Stewardship Taskforce and the VHA National Infectious Disease Service, HSR’s Evidence Synthesis Program (ESP) Center in Minneapolis created an evidence map to describe recent evidence on the effects and implementation processes of ASP strategies and programs in outpatient, primary care, emergency room (ER), and/or urgent care settings. ESP investigators also completed a systematic review of prioritized studies; these were randomized controlled trials or comparative observational studies conducted in primary care and/or ER settings that investigated audit and feedback, clinical decision support systems (CDSS; embedded in electronic health records with computerized order entry), or multicomponent ASPs. The ESP team searched MEDLINE, Embase, and Scopus for eligible studies published January 1, 2013–September 3, 2024. The team did not rate the certainty of evidence.

Summary of Findings

The updated evidence includes 285 primary studies and 37 systematic reviews. Investigators prioritized 45 primary studies for more detailed data abstraction and synthesis; most of these were conducted in primary care.

Characteristics of studies included in the evidence map:

• Studies evaluating patient and/or clinician education only or with audit and feedback dominate the evidence base.
• Most studies were observational and conducted in primary care or ER/urgent care settings.
• Overall antimicrobial and inappropriate (or appropriate) prescribing rates were the most frequently reported outcomes. Patient treatment outcomes and healthcare use were also commonly reported.
• Few studies assessed staff satisfaction and acceptability, implementation costs and barriers, sustainability, or reach (e.g., the type and proportion of patients and prescribers involved).

Reported outcomes and characteristics of prioritized studies:

• Audit and feedback, CDSS, and multicomponent programs did not consistently reduce overall or inappropriate antimicrobial prescribing. Limited evidence indicates that these strategies and their combination also did not impact patient treatment outcomes or healthcare use.
• Audit and feedback approaches varied, with differences in feedback frequency, delivery formats, and reference groups for comparing prescribing rates.
• CDSS tools predominantly provided clinician education or antimicrobial recommendations.
• Audit and feedback and CDSS were the most frequently employed strategies (with or without education and other strategies) in multicomponent stewardship programs.
• Half of the studies were conducted in Europe. A substantial number occurred in national or regional health systems, including two in VHA.

Implications

There has been substantial growth in the evidence base for antimicrobial stewardship in outpatient settings, but much of this evidence is observational and focused on educating clinicians and/or patients with or without audit and feedback strategies. Findings from the prioritized studies suggest that current stewardship strategies in the outpatient setting do not consistently result in substantial reductions in overall or inappropriate antimicrobial prescribing. Additional resources and guidance will be helpful to aid facilities in implementation of ASPs. The CDC is updating the recommended core elements for outpatient stewardship to provide better support for current and future outpatient ASPs. There remains an urgent need for effective strategies or multicomponent ASPs that can be implemented and sustained on a large scale in the outpatient setting.

Limitations

The evidence map describes the characteristics of existing research and highlights gaps in certain areas but does not include assessment or detailed data abstraction or synthesis of studies involving non-prioritized settings or strategies. Also, because only English-language studies and reviews were included, relevant publications in languages other than English might have been missed.

Future Research

Future research should address additional patient outcomes (e.g., antimicrobial side effects), implementation costs and barriers, staff satisfaction and acceptability, sustainability, and patient and prescriber reach. In addition, studies are needed to better understand the optimal characteristics of audit and feedback and CDSS strategies.

Citation:

Narayan M, Landsteiner A, Byrd J, et al. Antimicrobial Stewardship Strategies and Programs in the Outpatient Setting: A Systematic Review and Evidence Map. Washington, DC: Evidence Synthesis Program, Health Systems Research, Office of Research and Development, Department of Veterans Affairs. VA ESP Project #09-009; 2025.

To view the full report, go to vaww.hsrd.research.va.gov/publications/esp/Antimicrobial-Stewardship.cfm (This report is available via Intranet only.)

How can VA leadership work with the ESP? Nominations for systematic review topics may be submitted to the program at any time. When you submit a topic nomination form, ESP Coordinating Center staff will work with you to determine the appropriate research approach and ESP product to address your questions of interest. Topics are selected and assigned to an ESP Center based on program capacity and alignment with VA national goals.

This Management Brief is provided to inform you about recent HSR findings that may be of interest. The views expressed in this article are those of the authors and do not necessarily reflect the position or policy of the Department of Veterans Affairs. If you have any questions or comments about this Brief, please email CIDER. The Center for Information Dissemination and Education Resources (CIDER) is a VA HSR Resource Center charged with disseminating important HSR findings and information to policy makers, managers, clinicians, and researchers working to improve the health and care of Veterans.

This report is a product of VA/HSR's Evidence Synthesis Program (ESP), which was established to provide timely and accurate synthesis of targeted healthcare topics of particular importance to VA managers and policymakers; and to disseminate these reports throughout VA.

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