Prevalence of Positive Penicillin Allergy Testing in Hospitalized Adult Patients: A Systematic Review and Meta-Analysis

Background: Inaccurate penicillin allergy labels in hospitalized patients are linked to antibiotic-related patient harm, emergence of highly resistant strains, and increased patient- and institution-related financial burden. Objective: The aim of the study was to calculate the pooled prevalence of positive penicillin allergy evaluation in inpatients through penicillin skin testing (PST) and/or a direct oral challenge (DOC). Secondary outcomes included the rate of adverse reactions after penicillin allergy evaluation, penicillin allergy removal from medical records after allergy assessment, and changes in antibiotic regimen to include penicillin- and/or β-lactam-based antibiotics for patients who tested negative via PST and/or DOC. Methods: We searched the PubMed and Embase databases for observational studies reporting the prevalence of penicillin allergy in hospitalized patients undergoing PST and DOC. Results: After literature review, we included 46 studies in our analysis. Thirty-six studies used PST for allergy evaluation, and of 6897 tested individuals, 444 (6.44%) patients tested positive, leading to a pooled prevalence of positive PST of 3.15% (95% confidence interval [CI]: 1.74-4.86, I² = 86.92%). Twenty-three studies used DOC for allergy evaluation, and of 2328 individuals, 51 (2.19%) patients tested positive, leading to a pooled prevalence of positive DOC of 1.19% (95% CI: 0.27-2.51, I² = 61.60%). Of 1310 individuals with negative PST and/or DOC, 1188 patients (90.7%) had their allergy label removed from their electronic health records. Conclusions: In this study, the pooled prevalence of positive inpatient penicillin allergy evaluations with both PST and DOC assessments was estimated to be less than 5%. Majority of hospitalized patients with negative PST and/or DOC assessments had their penicillin allergy labels removed from their medical records.