Beta-lactam allergy in Chinese patients and factors predicting genuine allergy

Abstract

IntroductionBeta-lactams (BL) are the most frequently reported drug allergy, but the vast majority of patients are found not to be genuinely allergic after evaluation. Few studies have investigated the clinical predictors of genuine BL allergy, and the prevalence in hospitalized Chinese patients is unknown.MethodsPatients admitted to a tertiary hospital in Hong Kong (HK) were analyzed to identify the prevalence and factors associated with the presence of BL allergy labels among hospitalized Chinese patients. A combined cohort of patients having completed allergy investigation for suspected BL allergies in the United Kingdom (UK) and HK were analyzed to identify predictors of genuine allergy.ResultsThe prevalence of BL allergy labels in hospitalized HK Chinese was 5%, which was associated with female gender and concomitant non-BL antibiotic allergy labels. The rate of genuine BL allergy patients referred for suspected allergies in the UK and HK cohort was only 14%. History of anaphylaxis and interval of less than a year since the index reaction were independent clinical predictors of genuine BL allergy. The negative predictive value of penicillin skin testing was 90%, confirming the need for drug provocation testing after negative skin testing. There was a high rate of confirmed piperacillin-tazobactam allergy.DiscussionThe estimated true prevalence of genuine BL allergy in hospitalized HK Chinese is around 0.5%. This high rate of BL mislabeling highlights the need for comprehensive allergy evaluation and screening. History of anaphylaxis and duration since the index reaction are important predictors of genuine allergy. Piperacillin-tazobactam allergy may pose a unique challenge in this population with a high prevalence of suspected allergies, surging antibiotic resistance, and lack of testing available.

Prevalence, Incidence, and Sensitization Profile of β-lactam Antibiotic Allergy in Hong Kong

“…Most self-reports of β-lactam antibiotic allergies are known to be false, and the pilot study found that after testing only approximately 10% of such reports were true allergies. 8 If the rate of misreported allergies were true, more than 7200 patients may need an evaluation for potentially misreported new β-lactam antibiotic allergies in 2018 alone. This variability has substantial implications for skin testing methods and allergy practices.…”

“…In addition, other centers should analyze the underreported incidence (rather than solely the prevalence) of new drug allergies in other populations.Sensitization patterns among patients with β-lactam antibiotic allergy vary across different regions and ethnicities, which may be attributed to different prescribing practices and possible genetic or geographic predispositions. Regional variations in sensitization patterns have been well reported in non-Chinese populations, and substantial variability across different cohorts was found 8.…”

“…A pilot study conducted in Hong Kong found a 5% prevalence of misreported β-lactam antibiotic allergy in a cohort of hospitalized patients and estimated a 0.5% prevalence of genuine allergy. 8 However, that pilot study was small and based on admissions to a single hospital over a 6-month period. 8 The overall and absolute prevalence of misreported β-lactam antibiotic allergy remains unknown.…”

Diagnostic procedures & practices in drug allergy/hypersensitivity: a survey of 13 Asian countries

“…Drug allergy is an immunologically mediated DHR that should not be confused with intolerance or side effect that is pharmacologically mediated [ 6 ]. For example, less than 15% of patients with reported beta-lactam allergies were found to have genuine allergy after evaluation, which is similar to western cohorts [ 4 ]. A good understanding of the pathomechanism of an adverse drug reaction is therefore crucial in the correct labelling of a patient's reaction as this has significant implications in clinical management, from choice of appropriate antibiotics to prevention of a catastrophic outcome due to re-exposure [ 7 ].…”

“…The prevalence of physician-reported drug allergies is 7.1% based on population-wide studies in Hong Kong [ 3 ]. Up to 14% of hospitalised patients have drug allergy labels [ 4 ]. The incidence of drug allergy or drug hypersensitivity reaction (DHR) has been reported to occur in 4.2 per 1,000 hospitalisations, based on a prospective large Asian cohort studies [ 5 ].…”