How to 'SAVE' antibiotics: effectiveness and sustainability of a new model of antibiotic stewardship intervention in the internal medicine area

Abstract

Background: Antibiotic stewardship (AS) is a cornerstone of the fight against antimicrobial resistance; however, evidence on the best practice to improve antibiotic prescription in various hospital settings is still scarce. This study aimed to measure the efficacy of a non-restrictive AS intervention in the internal medicine area of a tertiary-care hospital across a 3-year period.

Methods: The intervention comprised a 3-month 'intensive phase' based on education and guidelines provision, followed by 9 months of audits and feedback activities. The primary outcome was the overall antibiotic consumption measured as days of therapy (DOTs) and defined daily doses (DDDs). Secondary outcomes were carbapenem and fluoroquinolone consumption, all-cause in-hospital mortality, length of stay, incidence of Clostridioides difficile and carbapenem-resistant Enterobacterales bloodstream infections (CRE-BSIs). All outcomes were measured in the intervention wards comparing the pre-phase with the post-phase using an interrupted time-series model.

Results: A total of 145 337 patient days (PDs) and 14 159 admissions were included in the analysis. The intervention was associated with reduced DOTs*1000PDs (-162.2/P = 0.005) and DDDs*1000PDs (-183.6/P ≤ 0.001). A sustained decrease in ward-related antibiotic consumption was also detected during the post-intervention phase and in the carbapenem/fluoroquinolone classes. The intervention was associated with an immediate reduction in length of stay (-1.72 days/P < 0.001) and all-cause mortality (-3.71 deaths*100 admissions/P = 0.002), with a decreasing trend over time. Rates of Clostridioides difficile infections and CRE-BSIs were not significantly impacted by the intervention.

Conclusions: The AS intervention was effective and safe in decreasing antibiotic consumption and length of stay in the internal medicine area. Enabling prescribers to judicious use of antimicrobials through active participation in AS initiatives is key to reach sustained results over time.

Keywords: Antibiotic stewardship; Antimicrobial resistance; Behaviour change intervention; Quality improvement.