The revolving door: antibiotic allergy labelling in a tertiary care centre

Abstract

BACKGROUND: Patients frequently report antibiotic allergies, however only 10% of labelled patients have a true allergy. AIM: We investigated the documentation of antibiotic "allergy" labels (AALs) and the effect of labelling on clinical outcomes, in a West Australian adult tertiary hospital. METHODS: Retrospective cross-sectional analysis of patients captured in the 2013 and 2014 National Antimicrobial Prescribing Surveys. Data was collected on documented antibiotic adverse drug reactions, antibiotic cost, prescribing appropriateness, prevalence of multi-drug resistant organisms, length of stay, intensive care admission, and readmissions. RESULTS: Of 687 patients surveyed, 278 (40%) were aged 70 or above, 365 (53%) were male and 279 (41%) were prescribed antibiotics. AALs were recorded in 122 (18%) patients and the majority were penicillin labels (n = 87; 71%). Details of AALs were documented for 80 of 141 (57%) individual allergy labels, with 61 describing allergic symptoms. Patients with beta-lactam allergy labels received fewer penicillins (p = 0.0002) and more aminoglycosides (p = 0.043) and metronidazole (p = 0.021) than patients without beta-lactam labels. Five patients received an antibiotic that was contraindicated according to their allergy status. Patients with AALs had significantly more hospital readmissions within 4 weeks (p = 0.001) and 6 months (p = 0.025) of discharge, compared with unlabelled patients. The majority (81%) of readmitted labelled patients had major infections. CONCLUSIONS: AALs are common but poorly documented in hospital records. Patients with AALs are significantly more likely to require alternative antibiotics, and hospital readmissions. There may be a role for antibiotic allergy delabelling to mitigate the clinical and economic burdens for patients with invalid allergy labels.