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Patients with penicillin allergy experience worse outcomes in bacterial pneumonia

Published: September 28, 2022

A penicillin (PCN) allergy label is common, and is associated with delay in initiation of antibiotics, use of alternative antibiotic regimens, and worse outcomes of treatment. In bacterial pneumonia, PCNs are a first-line treatment option. Data on the impact of PCN allergy label on patient outcomes following bacterial pneumonia have been limited.

In a retrospective matched cohort study recently published in The Journal of Allergy and Clinical Immunology: In Practice, Kaminsky and colleagues used TriNetX, a web-based tool for population cohort research, to identify adult bacterial pneumonia patients with and without a PCN allergy label. The two cohorts were matched on baseline demographics and comorbidities. The authors then examined 30-day clinical outcomes, antibiotic use patterns, and risk of adverse drug events.

There were 68,748 patients with bacterial pneumonia and PCN allergy label in one cohort, and 68,748 patients with bacterial pneumonia but without PCN allergy label in the second cohort. Within 30 days of bacterial pneumonia diagnosis, patients with PCN allergy label, as compared to patients without PCN allergy label, had higher risk of worse clinical outcomes including: hospitalization (69.2% compared to 56.2%), acute respiratory failure (40.1% compared to 35.3%), intubation (8.6% compared to 7.3%), and need for intensive care (14.0% compared to 12.6%). The mortality rate was also higher for patients with PCN allergy label (6.2%) compared to patients without PCN allergy label (5.7%). Patients with PCN allergy label were less likely to be given PCNs and cephalosporins, but more likely to receive other classes of antibiotics including fluoroquinolones, carbapenems, monobactams, and aminoglycosides. PCN allergy label was also associated with increased risk of adverse drug events including Clostridioides difficile infection (5.75% compared to 5.12%), drug-induced rash (0.83% compared to 0.39%), acute kidney injury (23.6% compared to 20.4%), and toxic liver disease (0.32% compared to 0.22%). This study provides evidence of worse outcomes of bacterial pneumonia in association with a PCN allergy label. As many of these patients are not truly PCN allergic once further evaluated by history and/or testing, PCN allergy de-labeling efforts are warranted for optimizing antibiotic use and improving outcomes in patients with pneumonia.

The Journal of Allergy and Clinical Immunology: In Practice is an official journal of the AAAAI, focusing on practical information for the practicing clinician.

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