Prescribing trends before and after implementation of an antimicrobial stewardship program

Abstract

Objectives: Antimicrobial stewardship programs are recommended to reduce antimicrobial resistance by reducing inappropriate use of antimicrobials. We implemented an antimicrobial stewardship program and aimed to evaluate its effect on broad-spectrum antimicrobial use.

Design, setting and participants: Observational study with historical control using interrupted time series analysis conducted in a tertiary referral hospital. Hospital inpatients prescribed restricted antimicrobials for non-standard indications, where approval had expired or without approval.

Intervention: Baseline period of 30 months immediately followed by an 18-03 intervention period commencing January 2011.

Main outcome measures: Number and type of interventions made by antimicrobial stewardship team; monthly rate of use of broad-spectrum antimicrobial agents (in defined daily doses/1000 occupied bed-18s).

Results: The antimicrobial stewardship team made 1104 recommendations in 779 patients during the 18-03 intervention period. In 64% of cases, the recommendation was made to cease or de-escalate the antimicrobial therapy, or to change from intravenous to oral therapy. The introduction of the intervention resulted in an immediate 17% (95% CI, 13%-20%) reduction in broad-spectrum antimicrobial use in the intensive care unit and a 10% (95% CI, 4%-16%) reduction in broad-spectrum antimicrobial use outside the intensive care unit. Reductions were particularly seen in cephalosporin and glycopeptide use, although these were partially offset by increases in the use of β-lactam-β-lactamase inhibitors.

Conclusions: The introduction of an antimicrobial stewardship program, including postprescription review, resulted in an immediate reduction in broad-spectrum antimicrobial use in a tertiary referral centre. However, the effect of this intervention reduced over time.