Prevalence of antibiotic allergy labels in a tertiary referral center in Belgium.

Abstract Background Antibiotic (AB) allergies are amongst the most frequently occurring adverse drug reactions. In US literature, AB allergy labels (AAL) are reported in 10-15% of patients’ charts, however, large-scale European analyses are scarce. Objectives To retrospectively assess the prevalence of AAL in a tertiary referral hospital in Belgium between 2010 and 2018. Methods Patients that consulted and/or were hospitalized during the study period, who had been labeled with an AB allergy were selected for further analysis. Results Out of 1 009 598 unique patients, 28 147 patients (3%) were registered with one or more AAL, being 1% of out- (n= 9 562) and 7% of inpatients (n= 18 585). Women were more likely to carry an AAL (68%) compared with men (32%, p Conclusion With an overall prevalence of 3%, the burden of AAL is less in our Western European center compared with US reports. However, this prevalence most likely still represents an overestimation of genuine AB allergic patients since most labels lack confirmation and/or specifications. Our work indicates knowledge on the local epidemiology of AAL is necessary to estimate the impact of better allergy labeling and delabeling strategies.