Antibiotic Allergy Labels Negatively Affect Patient Outcomes

New research from Australia found high rates of inappropriate prescribing in children with antibiotic allergy labels (AAL).

Children with AALs were significantly more likely to receive restricted antibiotics and had a longer length of stay compared with non-allergic controls.

According to investigators led by Laure F. Pittet, MD, PhD, this marked the first study to record such rates. They added that AALs placed a significant burden on the health system through higher medication costs, increased length of stay and poorer treatment outcomes.

β-lactam antibiotics are the most implicated with up to 75% of patients labelled with these allergies before the age of 3 years.

Additionally, prior studies showed that more than 90% of children with non-immediate reactions to amoxicillin do not have reproducible “allergic” reactions when re-challenged with the same drug, which effectively “de-labels” them.

In the study, Pittet and colleagues evaluated the prevalence of antibiotic allergy in an Australian tertiary pediatric center and focused on accuracy of allergy documentation in the electronic medical record (EMR) and referral for drug allergy assessment.

The appropriateness of subsequent antibiotic prescribing and impact on hospital treatment was also evaluated.

The Study

The investigators gathered data from a retrospective study of patients admitted to the Royal Children’s Hospital Melbourne (RCH) in Melbourne between April 30, 2016, and January 30, 2018.

During the study, a total of 204,413 patient encounters for 98,912 children at RCH were noted.

The hospital’s electronic medical record (EMR) was searched in April 2018, and a report was generated that detailed all patients with at least 1 AAL who had an encounter with the hospital since the introduction of the EMR on April 30, 2016.

The study involved a descriptive analysis of the burden of AAL on the hospital over a 21-month period and a subset analysis of patients over a 12-month period who had a documented allergy to either amoxicillin, penicillin or cefalexin and required treatment with intravenous (IV) antibiotics.

Proportions were compared using Fisher’s exact test, and data were analyzed using Stata v.13 [StataCorp, College Station, TX].

The Findings

The investigators recorded 938 children (1.0%) who had at least 1 AAL recorded in the EMR at the start of their admission. A total of 5145 encounters took place.

Penicillin was the most implicated antibiotic class in drug allergy (n = 439, 46.6%), followed by cephalosporins (n = 266, 28.3%), macrolides (n = 112, 11.9%), sulphonamides (n = 91, 9.7%), glycopeptides (n = 68, 7.2%), fluoroquinolones (n = 15, 1.6%) and aminoglycosides (n = 14, 1.5%).

Symptoms of the allergic reaction were documented in 912 (86.9%) of all allergies with rash accounting for more than half (n = 532, 58.3%).

Hospital stay was longer in the AAL patients (median 4.7 days; IQR 2.3-9.2) compared to the non-allergic patients (median 3.9 days; IQR 1.9-6.8; P = 0.02).

Also, children with an AAL were more likely to be prescribed a restricted antibiotic (aOR 3.03; 95%CI, 1.45-6.30; P = 0.003) with restricted antibiotics used in 53.0% of hospital admissions for those with an AAL compared with 26.7% for non-allergic patient.

The investigators noted that the high rate of inappropriate prescribing exceeded that of a previous point-prevalence survey at the same hospital that showed 28% of prescriptions were inappropriate based on the infection being treated.

They added that limited clinician knowledge about antibiotic allergy and a lack of clarity in EMR design were “key drivers” of inadequate documentation, and proposed changes in the EMR and in revised allergy labels.

“Several novel approaches, such as pharmacist-led patient review and revision of allergy labels and EMR-embedded support tools prompting prescribers to update allergy details have been shown to improve the quality of allergy documentation,” the team wrote.

The study, “Impact of Antibiotic Allergy Labels on Patient Outcomes in a Tertiary Pediatric Hospital,” was published online in the British Journal of Clinical Pharmacology.