Clinical and Economic Outcomes of Penicillin Skin Testing as an Antimicrobial Stewardship Initiative in a Community Health System

Abstract

Background Penicillin skin testing (PST) is a novel way to reduce the use of broad-spectrum agents in penicillin-allergic patients. This study evaluated the outcomes of patients with antimicrobials prescribed with and without PST in a community health system. Methods We performed a quasi-experimental study that compared an intervention group of 100 patients who completed PST over an open enrollment period beginning January 2016 with a matched control group of 100 patients who were penicillin allergic. Patients in the control group were matched to infection diagnosis codes of members of the PST group and randomly selected and matched on a 1:1 basis. The primary outcome was noncarbapenem beta-lactam days of therapy (DOT). The secondary outcome assessed the average cost of antimicrobial therapy for the intervention group before and after PST. Results Seventy of the 98 patients (71%) who tested negative had changes directly made to their antimicrobial regimens. Beta-lactam DOT for the PST group were 666/1094 (60.88%, with 34.82% being a penicillin specifically). Beta-lactam DOT for the control group consisted of 386/984 (39.64%, with 6.4% being a penicillin specifically). The chi-square test of homogeneity for beta-lactam DOT between the 2 groups was significant ( P < .00001). Changes to the antimicrobial regimen after PST saved the average patient $353.03 compared with no change in the pre-PST regimen ( P = .045). Conclusions PST led to immediate antimicrobial de-escalation in the majority of patients who tested negative. This led to a significant increase in beta-lactam usage, specifically penicillins. These benefits were also associated with significant cost savings to patients.

Penicillin Allergy Skin Testing in the Inpatient Setting

“…Given current efforts to optimize antimicrobial use and combat the emergence of antimicrobial resistance, there is a current call to action regarding reassessment of penicillin allergy labels among hospitalized patients. Fortunately, there are a growing variety of inpatient PST models to learn from [9,16,23,27,28,29,31]. Collectively, they demonstrate significantly improved clinical outcomes including increased use of preferred beta-lactam therapy for infection management, decreased healthcare costs, and increased quality-adjusted life years for patients.…”

“…However, given the limited availability of allergists in many inpatient settings, numerous allergists support the expansion of PST services by other trained healthcare professionals, such as pharmacists, infectious diseases (ID) fellow physicians, nurses, emergency medicine physicians, or a combination of providers [9,10,13,27,28,29,30,31]. A growing number of successful PST services now function as part of antimicrobial stewardship programs [23,27,28]. These antimicrobial stewardship personnel aim to optimize antimicrobial use and possess the expertise to maneuver the unintended consequences of a specific patient’s penicillin allergy label.…”

“…Physicians and nurses are usually able to bill for performing the PST service; yet, pharmacist-performed PST typically only bills for the cost of supplies to perform the test. Fortunately, there are some published examples demonstrating cost-effectiveness of PST services, which should allow even a pharmacist-led service to justify the time spent on such a program [27,32,33]. Jones et al described an average antimicrobial acquisition cost-saving of $353.03 per patient among all who received a PST at their local community hospital, even after considering PST drug supply costs of $140 per test [27].…”

“…Fortunately, there are some published examples demonstrating cost-effectiveness of PST services, which should allow even a pharmacist-led service to justify the time spent on such a program [27,32,33]. Jones et al described an average antimicrobial acquisition cost-saving of $353.03 per patient among all who received a PST at their local community hospital, even after considering PST drug supply costs of $140 per test [27]. King et al described a similar antimicrobial cost-savings of $297 per patient who was tested and switched to a beta-lactam antimicrobial [32].…”

Regulatory approval, implementation, and brief assessment of a pharmacist‐ and pharmacy trainee‐administered penicillin allergy assessment and skin testing program

“…Allergy reconciliation and penicillin allergy skin testing are validated methods for evaluating IgE‐mediated penicillin allergies and safely introducing the use of appropriate, preferred beta‐lactam therapy 1,3,14 . This optimization of antimicrobial therapy is not only clinically beneficial, but has also been shown to reduce costs associated with antimicrobial regimens 10,15‐17 . Resource limitations in some health care systems have led to the underutilization of allergy assessment and skin testing 18 .…”