An institutional review of antimicrobial stewardship interventions

•14654 antimicrobial therapy interventions were retrieved from 2009 to 2012.•Inappropriate dosing (39.0%) was the most frequently encountered.•Serious adverse drug events were avoided in 20.7% of evaluable interventions.•Stewardship programmes could be cost effective by improving quality of care. In order to combat increasing rates of bacterial resistance, many institutions have implemented antimicrobial stewardship programmes (ASPs) to improve antibiotic use. To ascertain the potential impact of our stewardship programme at Baylor St Luke's Medical Center (Houston, TX), antimicrobial-related interventions were analysed over a 4-year period. ASP recommendations related to antimicrobial therapy from 2009 to 2012 were retrieved from the hospital electronic database and were retrospectively reviewed. The number of interventions for each time period was adjusted to the hospital census data. The interventions were randomly assessed and categorised for clinical significance based on established institutional guidelines. In total, 14654 non-duplicate antimicrobial therapy interventions were retrieved, of which 11874 (81.0%) were audited for accuracy. Approximately 13 interventions were made per 1000 patient-days, but there were no significant patterns observed regarding the number of interventions performed from month to month (range 8–21). The most frequent types of interventions were related to inappropriate dosing (39.0%), antimicrobial selection (20.5%) and drug allergy (13.0%). Serious adverse drug events (ADEs) were potentially avoided in 20.7% of all interventions. Cumulative potential cost avoidance was more than US$6.5 million. In our institution, proper drug and dose selection were the major components of the ASP. Without focusing solely on reduction of drug acquisition costs, implementation of an ASP could still be cost effective by improving the quality of patient care and avoiding ADEs with serious consequences.