The impact of penicillin allergy de-labelling on the WHO AWaRe antibiotic categories: a retrospective cohort study

Assessing the rationale of prescribing carbapenems among hospitalized patients with documented penicillin allergy: implications for stewardship

Background

A reported history of penicillin allergy frequently leads to the prescription of carbapenems as a substitute for penicillin to avoid allergic reactions. Such self-reported allergies need to be accurately characterized to identify targeted antibiotic stewardship interventions that potentially minimize unnecessary carbapenem use.

Design

Retrospective cohort study.

Method

The proportion of hospitalized patients with penicillin allergy history receiving carbapenem prescriptions was evaluated between January 1st, 2017 and December 31st, 2018 at the University Hospital Basel, Switzerland. The appropriateness of carbapenem prescription of each patient was evaluated using institutional guidelines based on previously published recommendations.

Results

Our analysis revealed that among 212 patients with recorded penicillin allergy, of the 247 carbapenem treatment episodes, 79 (32%) were unjustified. Abdominal and lower respiratory tract infections were most frequently associated with inappropriate carbapenem use (OR 2.64, 95% CI 1.22-5.71, P = .014 and OR 2.26, 95% CI 1.08-4.73, P = .031). The recorded allergy type was not documented or unclear in 153 patients (72%) and penicillin allergy was only confirmed in 2 patients (0.9%). Inconsistencies in allergic symptom documentation and allergy types were found between the institution's two software programs.

Conclusion

While a multimodal approach to identify and accurately label penicillin allergies remains essential to reduce inappropriate carbapenem use, our findings highlight the need for comprehensive and easily accessible guidelines for carbapenem utilization and structured history-based allergy assessment as an initial screening tool, embedded in a tailored digital allergy record template.

Impact of penicillin allergy records on antimicrobial prescribing in hospitalised patients

BACKGROUND

The overdiagnosis of penicillin allergy and misclassification of non-truly allergic reactions is a growing public health problem, associated with the overuse of broad-spectrum and restricted antimicrobials. We aimed to evaluate the impact of penicillin allergy status on antimicrobial prescribing.

METHODS

A retrospective study of inpatients with a documented penicillin allergy receiving antimicrobials was conducted from 1 April to 1 July 2021. Antimicrobial prescribing and clinical characteristics were compared between patients with an active penicillin allergy label and those whose label was removed following antimicrobial stewardship team review. Antimicrobials were classified in two categories: i) 'Access' (recommended), ii) 'Watch and Reserve' (restricted) according to WHO AWaRe classification, a tool to guide appropriate antibiotic use.

RESULTS

437 patients with a documented penicillin allergy receiving antimicrobials were included. 353 patients with an active penicillin allergy label, more frequently received antimicrobials from the 'Watch and Reserve list' (283;80% vs 30;37%; p<0.001). In contrast, 84 patients who were de-labelled received more often antimicrobials from the 'Access list' (53;63% vs 64;18%; p<0.001).

CONCLUSIONS

Penicillin allergy reviews and de-labelling strategies may reduce the use of restricted antimicrobials under the 'Watch and Reserve list'. This practice should be encouraged and reinforced in all hospitals.

Impact of penicillin allergy labels on surgical site infections in a large UK cohort of gastrointestinal surgery patients

Objectives

Studies in the USA, Canada and France have reported higher surgical site infection (SSI) risk in patients with a penicillin allergy label (PAL). Here, we investigate the association between PALs and SSI in the UK, a country with distinct epidemiology of infecting pathogens and range of antimicrobial regimens in routine use.

Methods

Electronic health records and national SSI surveillance data were collated for a retrospective cohort of gastrointestinal surgery patients at Cambridge University Hospitals NHS Foundation Trust from 1 January 2015 to 31 December 2021. Univariable and multivariable logistic regression were used to examine the effects of PALs and the use of non-β-lactam-based prophylaxis on likelihood of SSI, 30 day post-operative mortality, 7 day post-operative acute kidney injury and 60 day post-operative infection/colonization with antimicrobial-resistant bacteria or Clostridioides difficile.

Results

Our data comprised 3644 patients and 4085 operations; 461 were undertaken in the presence of PALs (11.3%). SSI was detected after 435/4085 (10.7%) operations. Neither the presence of PALs, nor the use of non-β-lactam-based prophylaxis were found to be associated with SSI: adjusted OR (aOR) 0.90 (95% CI 0.65-1.25) and 1.20 (0.88-1.62), respectively. PALs were independently associated with increased odds of newly identified MRSA infection/colonization in the 60 days after surgery: aOR 2.71 (95% CI 1.13-6.49). Negative association was observed for newly identified infection/colonization with third-generation cephalosporin-resistant Gram-negative bacteria: aOR 0.38 (95% CI 0.16-0.89).

Conclusions

No evidence was found for an association between PALs and the likelihood of SSI in this large UK cohort, suggesting significant international variation in the impact of PALs on surgical patients.

The Burden of Self-Reported Antibiotic Allergies in Health Care and How to Address It: A Systematic Review of the Evidence

BACKGROUND

Antibiotics are the first-line treatment for bacterial infections; however, overuse and inappropriate prescribing have made antibiotics less effective with increased antimicrobial resistance. Unconfirmed reported antibiotic allergy labels create a significant barrier to optimal antimicrobial stewardship in health care, with clinical and economic implications.

OBJECTIVE

A systematic review was conducted to summarize the impact of patient-reported antibiotic allergy on clinical outcomes and various strategies that have been employed to effectively assess and remove these allergy labels, improving patient care.

METHODS

The review was undertaken using the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A critical appraisal was conducted on all studies and a narrative synthesis was performed to identify themes.

RESULTS

Four themes emerged: the prevalence of antibiotic allergy, impact of antibiotic allergy on antimicrobial prescribing, impact of antibiotic allergy on clinical outcomes, and delabeling strategies to improve clinical outcomes. Of the 32 studies, including 1,089,675 participants, the prevalence of reported antibiotic allergy was between 5% and 35%. Patients with a reported antibiotic allergy had poorer concordance with prescribing guidelines in 30% to 60% of cases, with a higher use of alternatives such as quinolone, tetracycline, macrolide, lincosamide, and carbapenem and lower use of beta-lactam antibiotics. Antibiotic allergy delabeling was identified as an intervention and recommendation to advance the state of the science.

CONCLUSIONS

There is substantial evidence within the literature that antibiotic allergy labels significantly impact patient clinical outcomes and a consensus that systematic assessment of reported antibiotic allergies, commonly referred to as delabeling, improves the clinical management of patients.

Characterizing Antibiotic Allergy Labels in a Large UK Hospital Population to Inform Antimicrobial Stewardship and Delabeling Assessment Strategy

BACKGROUND

Antibiotic allergy labels are important barriers to treatment and antimicrobial stewardship, but their prevalence in UK hospitals is poorly described.

OBJECTIVE

To ascertain the prevalence and characteristics of antibiotic allergy labels in a large UK hospital setting and estimate the proportion of penicillin allergy labels for which point-of-care (POC) delabeling assessment would be appropriate.

METHODS

Electronic health records data were analyzed from all patients treated at Cambridge University Hospitals NHS Foundation Trust in 2019. Validated POC delabeling risk stratification criteria were retrospectively applied to penicillin allergy labels.

RESULTS

Recorded reactions to antibiotics were present in 11.8% of all patients (32,148 of 273,216), 16.3% of inpatients (13,874 of 85,230), and 9.7% of outpatients (18,274 of 187,986). Penicillins were the commonest reaction precipitant described (9.0% of patients; 24,646 of 273,216), followed by sulfonamides/trimethoprim (1.4%; 3869 of 273,216) and macrolides/lincosamides (1.3%; 3644 of 273,216). A total of 3.9% of inpatients had recorded reactions to >1 antibiotic class (3348 of 85,230). Cutaneous manifestations were the most commonly described reaction features (40.7% of labels; 15,821 of 38,902). Of 15,949 labels describing probable or possible penicillin "allergy" with sufficient detail to allow for the retrospective assessment of POC delabeling suitability, 1702 were deemed suitable for removal or downgrading of the label to "intolerance" without further investigation (10.7%), 11,887 were appropriate for POC assessment using an oral penicillin challenge (OPC) or OPC with prior bedside skin testing (74.5%), and 2360 were identified as unsuitable for any form of POC assessment (14.8%).

CONCLUSIONS

Antibiotic allergy labels are highly prevalent in a UK hospital setting. A large proportion of penicillin allergy labels may be suitable for POC delabeling assessment.

Addressing the Challenges of Penicillin Allergy Delabeling With Electronic Health Records and Mobile Applications

Allergy labels are common, often incorrect, and potentially harmful. There are many opportunities for clinical decision support (CDS) tools integrated in the electronic health record (EHR) and mobile apps to address the challenges with drug allergy management, including penicillin allergy delabeling (PADL). Effective delabeling solutions must consider multidisciplinary clinical workflow and multistep processes, including documentation, assessment, plan (eg, allergy testing and referral), record update, drug allergy alert management, and allergy reconciliation over time. Developing a systematic infrastructure to manage allergies across the EHR is critical to improve the accuracy and completeness of a patient's allergy and avoid inadvertently relabeling. Improving the appropriateness and relevancy of drug allergy alerts is important to reduce alert fatigue. Using alerts to guide clinicians on appropriate antibiotic use may reduce unnecessary β-lactam avoidance. To date, EHR CDS tools have facilitated non-allergists to provide PADL at the point of care. A mobile app was shown to support PADL and provide specialist support and education. Future research is needed to standardize, integrate, and evaluate innovative CDS tools in the EHR to demonstrate patient safety and clinical utility and facilitate wider adoption.

Negative impact of penicillin allergy labels on antibiotic use in hospitalized patients in Chinese Mainland

Background

Penicillin allergy labels have gained increasing global attention. However, to date, there are no data on the influence of penicillin allergy labels on patients in Chinese mainland.

Methods

This retrospective study reviewed the electronic health record (EHR) of hospitalized patients between June 1, 2018 and May 31, 2019. Patients with a penicillin allergy record were included in the allergy group. Every allergy patient was matched with 4 control patients by using propensity score-based matching to make sure the following were balanced: age, sex, date of admission, and the main diagnosis. We estimated the prevalence of penicillin allergy labels and compared the antibiotic prescription patterns and other clinical outcomes between the 2 groups.

Results

A total of 5691 patients and 22 585 patients were included in the allergy group and control group, respectively. The prevalence of penicillin allergy labels among the hospitalized patients in this study was 4.00%. Compared to the control group, significantly fewer patients in the allergy group were prescribed penicillins and most cephalosporins, while a larger proportion of allergy patients received clindamycin (10.02% vs 5.41%, p < 0.001) and some higher-class antibiotics, such as monobactams (1.81% vs 0.54%, p < 0.001), carbapenems (5.80% vs 4.98%, p = 0.014), macrolides (0.60% vs 0.25%, p < 0.001), and quinolones (17.62% vs 12.40%, p < 0.001). Allergy patients also had longer hospital stays and a greater need to consult infection specialists.

Conclusion

The prevalence of penicillin allergy labels was 4.00% in Chinese hospitalized patients. Penicillin allergy labels could cause irrational antibiotic prescribing, prolonged hospital stays, and greater consultation needs.