Impact of an antimicrobial stewardship programme to optimize antimicrobial use for outpatients at an emergency department.

BACKGROUND: Antimicrobial stewardship programmes (ASPs) have been effective in optimizing antibiotic use for inpatients. However, an emergency department's fast-paced clinical setting can be challenging for a successful ASP.

AIM: In April 2015, an ASP was implemented in our emergency department and we aimed to determine its impact on antimicrobial use for outpatients.

METHODS: This was a single-centre study comparing the quality of antibiotic prescriptions between a one-year period before ASP implementation (November 2012 to October 2013) and a one-year period after its implementation (June 2015 to May 2016). For each period, antimicrobial prescriptions for all adult outpatients (hospitalized for <24h) were evaluated by an infectious disease specialist and an emergency department physician to assess compliance with local prescribing guidelines. Inappropriate prescriptions were then classified.

FINDINGS: Before and after ASP, 34,671 and 35,925 consultations were registered at our emergency department, of which 25,470 and 26,208 were outpatients. Antimicrobials were prescribed in 769 (3.0%) and 580 (2.2%) consultations, respectively (P < 0.0001). There were 484 (62.9%) and 271 (46.7%) (P < 0.0001) instances of non-compliance with guidelines before and after ASP implementation. Non-compliance included unnecessary antimicrobial prescriptions, 197 (25.6%) vs 101 (17.4%) (P<0.0005); inappropriate spectrum, 108 (14.0%) vs 54 (9.3%) (P=0.008); excessive treatment duration, 87 (11.3%) vs 53 (9.1%) (P>0.05); and inappropriate choices, 11 (1.4%) vs 15 (2.6%) (P>0.05).

CONCLUSION: The implementation of an ASP markedly decreased the number of unnecessary antimicrobial prescriptions, but had little impact on most other aspects of inappropriate prescribing.