Use of Penicillin Skin Testing as an Antimicrobial Stewardship Initiative: Clinical and Economic Evaluation at a Community Health System

Abstract

BackgroundCommonly reported penicillin allergies result in limited treatment options, increased healthcare costs, and increasing resistance with the use of broad-spectrum agents. By providing penicillin skin testing (PST) to patients with a penicillin allergy, there is potential to reduce the use of carbapenems, aztreonam, vancomycin, and other broad-spectrum agents, resulting in cost savings and unnecessary overuse. This study examined clinical and economic outcomes of antimicrobials prescribed before and after PST.MethodsThis nonrandomized, observational chart review examined adult patients admitted over an open enrollment period of 100 patients who completed PST for a self-reported penicillin allergy. The study included all patients who met inclusion criteria and completed the test per protocol. Administration of the test utilized a stewardship pharmacist-driven, nursing administered, protocol that has three phases: puncture, intradermal, and oral challenge (optional phase). The primary outcome assessed was change made to antimicrobial regimen directly related to PST. A secondary outcome assessed was cost savings associated with PST.ResultsOver 13 months, 116 patients were consulted for PST with 100 patients completing PST per protocol. Self-reported allergies consisted of IgE-mediated and unknown in 52% and 30% of patients respectively. Seventy-one of 98 patients who tested negative (73%) had changes directly made to their antimicrobial regimens related to PST after intervention from the stewardship pharmacist. Thirty-four patients who had received carbapenems were changed directly to a penicillin or cephalosporin. A previous evaluation at our institution showed an average total antimicrobial acquisition cost savings per patient to be $314.75, which would result in $22,347.25 in direct savings for all patients evaluated.ConclusionPST led to immediate antimicrobial de-escalation in the majority of patients who tested negative. Most of these patients were transitioned to optimal therapy or de-escalated from carbapenem therapy. A total direct cost savings for the institution over the course of 13 months exceeded $20,000. Our study confirmed the overall utility of PST as a cost effective antimicrobial stewardship tool, especially as a carbapenem-sparing strategy.Disclosures B. Jones, ALK: Consultant, Grant Investigator and Scientific Advisor, Consulting fee, Grant recipient and Speaker honorarium; C. Bland, ALK: Grant Investigator and Scientific Advisor, Grant recipient and Speaker honorarium