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

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 clinical pharmacists [11]. In 1977, the Infectious Diseases Society of America (IDSA) released a statement that clinical pharmacists may have a substantial impact on patient care, including in ID, contributing to the idea that a team of physicians collaborating with pharmacists presents the best way to combat inappropriate medication use. Pharmacist involvement has since been shown to restrict broad overutilized antimicrobial agents and reduce the rate of C. difficile infection by a significant amount [13].

In 1997 the IDSA and the Society for Healthcare Epidemiology of America (SHEA) published guidelines to assist in the prevention of the growing issue of resistance, mentioning the importance of antimicrobial stewardship [14]. A decade later they released joint guidelines for ASP implementation [15], and the Pediatric Infectious Disease Society (PIDS) joined them in 2012 to publish a joint statement acknowledging and endorsing stewardship [16]. In 2014, the Centers of Disease Control and Prevention (CDC) recommended that every hospital should have an ASP. As of 1 January 2017, the Joint Commission requires an ASP as a standard for accreditation at hospitals, critical access hospitals, and nursing care [17]. Guidelines for implementation of an ASP are currently available through the IDSA and SHEA [1,16].

ASP Interventions

There are 2 main strategies that ASPs have to combat inappropriate antimicrobial use, and each has its own set of systematic interventions. These strategies are referred to as “prospective audit with intervention and feedback” and “prior authorization” [6]. Although most ASPs will incorporate these main strategies, each institution typically creates its own strategies and regulations independently.

Prospective audit with intervention and feedback describes the process of providing recommendations after reviewing utilization and trends of antimicrobial use. This is sometimes referred to as the “back-end” intervention, in which decisions are made after antibiotics have been administered . Interventions that are commonly used under this strategy include discontinuation of antibiotics due to culture data, de-escalation to drugs with narrower spectra, IV to oral conversions, and cessation of surgical prophylaxis [6].