Preadmission Penicillin Allergy Evaluation Before Hematopoietic Stem Cell Transplantation Optimizes Febrile Neutropenia Treatment and Inpatient Resource Utilization

Abstract

Febrile neutropenia is a common complication of conditioning chemotherapy for hematopoietic stem cell transplant (HSCT), but a major barrier for optimal treatment of febrile neutropenia is historical penicillin allergies. Our group recently published a development of a clinical pipeline for delabeling penicillin allergies in adult patients planned to undergo hematopoietic stem cell transplant (HSCT). In this retrospective cohort study, we followed patients to evaluate their outcomes during inpatient admission for HSCT. We hypothesized that, among patients planned for HSCT with a self-reported penicillin allergy, completing penicillin allergy testing (amoxicillin ingestion challenge with or without concomitant penicillin skin testing) prior to HSCT admission would be associated with differences in inpatient treatment for febrile neutropenia (including antibiotic selection and timing of antibiotic administration) and improved inpatient resource utilization (including nursing and inpatient physician consults). We identified patients with a self-reported penicillin allergy who answered a penicillin allergy questionnaire and were subsequently admitted to our institution for HSCT. We divided the cohort into 2 groups: patients whose penicillin allergy was evaluated prior to admission (EPTA) and patients whose penicillin allergy was not evaluated prior to admission (NEPTA). We then performed comparison between the 2 groups for general clinical outcomes of HSCT admission (duration of admission, need for ICU transfer, readmission rate, etc.), febrile neutropenia treatment, and inpatient resource utilization. Statistics were calculated using the non-parametric two-tailed Fisher exact test for categorical outcomes and the non-parametric two-tailed Mann-Whitney U test for numerical outcomes RESULTS: Within our cohort, 35 patients completed penicillin allergy testing prior to HSCT admission (EPTA) and 44 patients did not (NEPTA). Demographics were similar between these groups, and there was no significant difference in the rate of febrile neutropenia during HSCT admission (EPTA 64% vs NEPTA 66%, p=1.00). EPTA patients were significantly more likely to receive standard first-line antibiotics (cefepime or ceftazidime) for febrile neutropenia (EPTA 95% vs NEPTA 65%, p=0.015) and time between febrile neutropenia onset and antibiotic administration was shorter (EPTA mean 66 mins vs NEPTA mean 121 mins, p=0.0058). No patients in the EPTA group experienced an immediate hypersensitivity reaction (hives, anaphylaxis, etc.) or severe cutaneous adverse reaction (SCAR) during HSCT admission. EPTA patients were also significantly less likely to require 1:1 nursing for antibiotic test doses, challenges, and desensitizations (EPTA 0% vs NEPTA 49%, p<0.0001); less likely to require inpatient allergy consult (EPTA 0% vs NEPTA 12%, p=0.031); and less likely to require inpatient antimicrobial stewardship consult (EPTA 0% vs NEPTA 13%, p=0.013) during their HSCT admission. In summary, patients who completed penicillin allergy testing prior to HSCT admission were more likely to receive first-line antibiotics and received antibiotics more rapidly for treatment of febrile neutropenia. Furthermore, patients who completed penicillin allergy testing prior to HSCT admission were less likely to require 1:1 nursing, inpatient allergy consults, and inpatient antimicrobial stewardship consults during HSCT admission.