Successful Piperacillin-tazobactam De-escalation Program as an Antimicrobial Stewardship Initiative

Background: Broad-spectrum antimicrobial use has been associated with the selection of resistant organisms, making antimicrobial de-escalation highly desirable to decrease exposure and contain costs.  Education is one of the most frequent tools employed by antimicrobial stewardship programs (ASP) to improve prescribing behavior. When used without active intervention however, this method is only marginally effective and lacks a sustained impact.  Clinical decision support (CDS) systems can be used to facilitate antimicrobial stewardship by more efficient targeting of interventions.

Objective: Piperacillin-tazobactam (P/T) was identified as a commonly used broad-spectrum agent suitable for a de-escalation project.  This initiative sought to utilize clinical pharmacists (CPs) as members of the ASP, and CDS to efficiently focus attention to possible candidates for de-escalation.

Methods: CDS was utilized to alert CPs to potential opportunities for P/T de-escalation when culture results and sensitivity became available.   CPs evaluated patients to confirm de-escalation was appropriate according to susceptibility report and standard criteria developed by the ASP.  CPs then suggested an alternative narrower agent to the patient care team.  All successful interventions, as well as courses that did not meet criteria for de-escalation, were recorded via CDS.  To monitor the sustainability of the initiative, patients that had therapy de-escalated prior to CP intervention were also tracked.  Percent of appropriate de-escalation and percent of de-escalation prior to intervention (as a surrogate for improvement in appropriate utilization of susceptibility results), were analyzed over time using a Chi square test for trend with a Mantel extension.  Time adjusted averages were calculated by linear trend.

Results: The rate of de-escalation of courses ranged from 44% during the pilot phase to 90%.  De-escalation increased linearly over the first month and then reached a plateau.  Rates of de-escalated courses were consistently above 80% with the time-adjusted average (n=11 remaining months).  De-escalation prior to intervention increased from 6% initially to as high as 77%.  De-escalation prior to intervention achieved a time-adjusted average of 60% by study completion.  Both trends were highly significant (p<0.001). 

Conclusions: These results suggest that CP interventions undertaken as an integral component of an institution's ASP improve targeted therapy.  As clinicians became more aware of the appropriate response to culture and susceptibility results, the need for interventions to maintain these improvements lessened over time.  A  CDS can be used to efficiently focus ASP clinician attention on potential intervention opportunities.