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Abstract

Introduction: Recent data suggests that patients labeled as having an antimicrobial allergy are at increased risk for in-hospital mortality [Reference 1]. Hypothesis: A reported beta-lactam (BL) allergy increases the risk of inappropriate empiric antibiotic therapy (IEAT) and mortality in patients with gram-negative bacteremia (GNB). Methods: A retrospective analysis of adult patients with GNB was conducted. Data analyzed included BL allergy status, demographics, IEAT, and in-hospital mortality. Co-morbidities were assessed using the McCabe Jackson score and the Charlson co-morbidity index. Severity of illness was evaluated using the APACHE II score. Patients were classified as BL-allergic or non-BL-allergic based on documentation in the medical record. Univariate and multivariate analyses were used to study BL allergy for its association with IEAT (primary endpoint) and with in-hospital mortality (secondary endpoint). Subgroup analyses in patients with healthcare-associated infections (HCAI) and multi-drug resistant organisms (MDRO) were also conducted. Results: A total of 294 patients were included. A BL allergy was noted in 54 patients (18.4%); the type of reaction was specified in only 14 (25.9%) of these patients. The mean APACHE II score was 17.6, and overall in-hospital mortality was 18.7%. HCAI infections and MDRO pathogens were present in 77.9% and 38.4% of patients, respectively. The genitourinary tract was the most common infection source (38.4%), and Escherichia coli was the most commonly cultured pathogen (43.6%). Although IEAT was more common in the allergic group than in the non-allergic group, this difference was not statistically significant (24.1% versus 20.4%, respectively, P > 0.05). In-hospital mortality was also similar between groups (18.5% versus 18.8%, respectively, P > 0.05). No significant differences were noted in either subgroup analysis. Conclusions: Outcomes were similar among patients with and without a BL allergy label in this cohort of patients with GNB. Additional studies are needed to explore the relationship between antimicrobial allergy and clinical outcomes in specific subpopulations. [Reference 1: Pharmacotherapy 2011;31:742-7.]