Measuring what matters in Antimicrobial Stewardship Programs to Demonstrate their Value

Reviewed by Cynthia T. Nguyen, PharmD, University of Chicago Medicine and Vanessa Stevens, PhD, University of Utah 

Measures of successful antimicrobial stewardship programs (ASPs) are not well-established. As antimicrobials are commonly inappropriately prescribed, new ASPs can demonstrate overall reductions in antimicrobial use and cost. However, these measures plateau over time and may not correlate well with the goal of ASPs to optimize antimicrobial use (AU) and patient outcomes. Consequently, ASPs are challenged with the need to identify quality indicators (QI) to measure their quality and value.

ASPs commonly measure AU to evaluate the impact of programs and policies over time. McGill and colleagues performed an update of the 2011 Emerging Infections Program point prevalence survey of AU among inpatients. The 2015 survey included approximately 13,000 randomly selected inpatients in 199 hospitals across 10 states and collected data concerning AU on the day of the survey or the day before. The survey quantified overall antimicrobial use and across specific classes and hospital ward types. 

Between 2011 and 2015, AU remained stable at approximately 50% of abstracted patients in both years. Overall, AU in most adult critical and non-critical care wards were similar across surveys, with increases noted for 2015 compared to 2011 in hematology/oncology wards (67.7% vs 56.9%) and neurology wards (43.6% vs. 29.6%), but these patient populations were a small proportion of the total. AU decreased from 32.0% in 2011 to 22.8% in 2015 among neonatal critical care patients. Trends in AU by antimicrobial class were largely stable, with slight decreases observed in the use of fluoroquinolones (11.9% in 2011 vs. 10.1% in 2015) and increases in the use of cephalosporins and carbapenems. 

O’Riordan and colleagues conducted a systematic review to identify and evaluate quality indicators (QIs) of hospital ASPs and appraise their methodological quality. QIs were defined as ‘measurable elements of practice performance for which there is evidence or consensus that they can be used to assess the quality of care provided’. Studies that described the development process and characteristics of ASP QIs were included. QIs were categorized as structural, process, or outcome QIs, classified into themes, and appraised based on their methodological quality.

A total of 229 QIs were identified from 16 studies and consisted of 75% process, 24% structural and 1% outcome indicators. Themes of process indicators included infection diagnostics, pharmacy-supported interventions, and disease-specific indicators. Themes of structural indicators included leadership, prescribing policies, and microbiology lab standards. The two outcomes indicators were monitoring clinical outcomes of patients receiving antibiotics and the rate of nosocomial CDI. There was a wide variation in the information and level of detail presented describing the methodological characteristics of the QI sets identified. 

Overall, ASPs are still lacking sufficient, well-established outcomes indicators. Process or structural indicators that have been linked to outcomes may be an acceptable alternative but are still indirect. The EIP point prevalence survey provides insights into AU at a large number of hospitals, but metrics focused on AU alone may not fully capture the impact of ASPs on patient outcomes. Despite challenges with confounding, identifying and validating outcomes measures will be important as ASPs try to generate buy-in with relevant stakeholders, such as patients and administrators. 


  1. Magill SS, O’Leary E, Ray SM, et al; Emerging Infections Program Hospital Prevalence Survey Team. Antimicrobial Use in US Hospitals: Comparison of Results from Emerging Infections Program Prevalence Surveys, 2015 and 2011. Clin Infect Dis. 2021 May 18;72(10):1784-1792. 
  2. O’Riordan F, Shiely F, Byrne S, Fleming A. Quality indicators for hospital antimicrobial stewardship programmes: a systematic review. J Antimicrob Chemother. 2021 May 12;76(6):1406-1419. 
We use cookies to help improve your experience