Clinical Review

Antimicrobial Stewardship Programs: Effects on Clinical and Economic Outcomes and Future Directions


From the Ernest Mario School of Pharmacy, Rutgers, The State University of New Jersey, Piscataway, NJ.



• Objective: To review the evidence evaluating inpatient antimicrobial stewardship programs (ASPs) with a focus on clinical and economic outcomes.

• Methods: Pubmed/MEDLINE and the Cochrane Database of Systematic Reviews were used to identify systematic reviews, meta-analyses, randomized controlled trials, and other relevant literature evaluating the clinical and economic impact of ASP interventions.

• Results: A total of 5 meta-analyses, 3 systematic reviews, and 10 clinical studies (2 randomized controlled, 5 observational, and 3 quasi-experimental studies) were identified for analysis. ASPs were associated with a reduction in antimicrobial consumption and use. However, due to the heterogeneity of outcomes measured among studies, the effectiveness of ASPs varied with the measures used. There are data supporting the cost savings associated with ASPs, but these studies are more sparse. Most of the available evidence supporting ASPs is of low quality, and intervention strategies vary widely among available studies.

• Conclusion: Much of the evidence reviewed supports the assertion that ASPs result in a more judicious use of antimicrobials and lead to better patient care in the inpatient setting. While clinical outcomes vary between programs, there are ubiquitous positive benefits associated with ASPs in terms of antimicrobial consumption,  C. difficile  infection rates, and resistance, with few adverse effects. To date, economic outcomes have been difficult to uniformly quantify, but there are data supporting the economic benefits of ASPs. As the number of ASPs continues to grow, it is imperative that standardized metrics are considered in order to accurately measure the benefits of these essential programs.


Key words:  Antimicrobial stewardship; antimicrobial consumption; resistance.


Antimicrobial resistance is a public health concern that has been escalating over the years and is now identified as a global crisis [1–3]. This is partly due to the widespread use of the same antibiotics that have existed for decades, combined with a lack of sufficient novel antibiotic discovery and development [4]. Bacteria that are resistant to our last-line-of-defense medications have recently emerged, and these resistant organisms may spread to treatment-naive patients [5]. Multidrug-resistant organisms are often found, treated, and likely originate within the hospital practice setting, where antimicrobials can be prescribed by any licensed provider [6]. Upwards of 50% of antibiotics administered are unnecessary and contribute to the problem of increasing resistance [7]. The seriousness of this situation is increasingly apparent; in 2014 the World Health Organization (WHO), President Obama, and Prime Minister Cameron issued statements urging solutions to the resistance crisis [8].

While the urgency of the situation is recognized today, efforts aimed at a more judicious use of antibiotics to curb resistance began as early as the 1960s and led to the first antimicrobial stewardship programs (ASPs) [9–11]. ASPs have since been defined as “coordinated interventions designed to improve and measure the appropriate use of antimicrobial agents by promoting the selection of the optimal antimicrobial drug regimen including dosing, duration of therapy, and route of administration” [1]. The primary objectives of these types of programs are to avoid or reduce adverse events (eg,  Clostridium difficile  infection) and resistance driven by a shift in minimum inhibitory concentrations (MICs) and to reverse the unnecessary economic burden caused by the inappropriate prescribing of these agents [1].

This article examines the evidence evaluating the reported effectiveness of inpatient ASPs, examining both clinical and economic outcomes. In addition, we touch on ASP history, current status, and future directions in light of current trends. While ASPs are expanding into the outpatient and nursing home settings, we will limit our review here to the inpatient setting.


Historical Background

Modern antibiotics date back to the late 1930s when penicillin and sulfonamides were introduced to the medical market, and resistance to these drug classes was reported just a few years after their introduction. The same bacterial resistance mechanisms that neutralized their efficacy then exist today, and these mechanisms continue to confer resistance among those classes [5].

While “stewardship” was not described as such until the late 1990s [12], institutions have historically been proactive in creating standards around antimicrobial utilization to encourage judicious use of these agents. The earliest form of tracking antibiotic use was in the form of paper charts as “antibiotic logs” [9] and “punch cards” [10] in the 1960s. The idea of a team approach to stewardship dates back to the 1970s, with the example of Hartford Hospital in Hartford, Connecticut, which employed an antimicrobial standards model run by an infectious disease (ID) physician and


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