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.

The effects of beta-lactam allergy relabeling on antibiotic prescribing practices

BACKGROUND

Beta-lactam antibiotic allergy labels are highly prevalent but rarely indicate an allergic intolerance. These patient-reported allergies lead to broad-spectrum antibiotic use, conferred resistance, increased expense, and adverse effects.

OBJECTIVE

To implement and assess the impact of a history-based clinical guideline that directs antibiotic management and beta-lactam allergy relabeling for patients reporting beta-lactam allergies.

METHODS

Patients with beta-lactam allergy labels were identified by our trained multidisciplinary team in diverse clinical settings. This quality improvement project was conducted to evaluate the safety and impact of the guideline on antibiotic use by comparing prescribing practices before and after guideline implementation.

RESULTS

A total of 79 patients with beta-lactam allergies were identified (penicillins-90%, cephalosporins-10%). After guideline implementation, outcomes of allergy relabeling included the following: (1) complete removal, indicating an unlikely true allergy (27%); (2) updated to detail successfully tolerated beta-lactam courses (48%); or (3) no change made to current label (25%). Beta-lactam antibiotic courses before and after guideline implementation compared with total antibiotic courses: allergy removed (44% vs 70%; P < .001), allergy updated (32% vs 68%; P < .001), and no change (27% vs 41%; P = .08). Compared with before guideline implementation, beta-lactam antibiotics were 3 times more likely to be prescribed after allergy assessment (odds ratio, 3.22; 95% confidence interval, 2.4-4.3; P < .05).

CONCLUSION

The implementation of the beta-lactam allergy clinical guideline resulted in most patients' allergy labels being removed or advantageously updated. These allergy label changes correlated with a substantial increase in the percentage of beta-lactam antibiotics prescribed. After guideline implementation, beta-lactam antibiotics had a 3-fold increased odds of being prescribed independent of allergy label outcome.

Penicillin Allergy Delabeling: A Multidisciplinary Opportunity

The penicillin allergy label has been consistently linked with deleterious effects that span the health care spectrum, including suboptimal clinical outcomes, the emergence of bacterial resistance, and increased health care expenditures. These risks have recently motivated professional organizations and public health institutes to advocate for the implementation of penicillin allergy delabeling initiatives; however, the burden of delabeling millions of patients is too expansive for any one discipline to bear alone. This review presents the unique perspectives and roles of various stakeholder groups involved in penicillin allergy diagnosis, assessment, and delabeling; we emphasize opportunities, barriers, and promising areas of innovation. We summarize penicillin allergy methods and tools that have proven successful in delabeling efforts. A multidisciplinary approach to delabeling patients with reported penicillin allergy, bolstered by evidence-based clinical practices, is recommended to reduce the risks that associate with the penicillin allergy label.

Evaluation of a Pharmacist-Led Penicillin Allergy Assessment Program and Allergy Delabeling in a Tertiary Care Hospital

IMPORTANCE

Penicillin allergies are frequently mislabeled, which may contribute to use of less-preferred alternative antibiotics.

OBJECTIVE

To evaluate a pharmacist-led allergy assessment program's association with antimicrobial use and clinical outcomes.

DESIGN, SETTING, AND PARTICIPANTS

A pharmacist-led allergy assessment program was launched in 2 phases (June 1, 2015, and November 2, 2016) at a single-center tertiary referral hospital. The longitudinal cross-sectional study included all study period adult admissions; hospitalwide outcomes were assessed by segmented regression. Individual outcomes were assessed within an embedded propensity score-matched case-control study of inpatients undergoing comprehensive allergy assessment following self-report of penicillin allergy. Analysis occurred from March 1, 2020, to February 29, 2020.

EXPOSURES

The longitudinal study analyzed hospital-level outcomes over 3 periods: preintervention (15 months), phase 1 (structured allergy history alone, 16 months), and phase 2 (comprehensive assessment including penicillin skin testing, 52 months). The case-control study defined cases as individuals undergoing comprehensive allergy assessment.

MAIN OUTCOMES AND MEASURES

Hospital-level outcomes included antibiotic days of therapy per 1000 patient-days and hospital-acquired Clostridioides difficile infection (CDI) incidence per 10 000 patient-days. Individual outcomes included antibiotic selection, overall survival, and CDI-free survival.

RESULTS

Longitudinal analysis spanned 2014-2020 (median admissions, 46 416 per year; interquartile range [IQR], 46 001-50 091 per year). Hospitalwide, allergy histories were temporally associated with decreased use of nonpenicillin alternative antibiotics (rate ratio, 0.87; 95% CI, 0.79-0.97) and high-CDI-risk antibiotics (rate ratio, 0.91; 95% CI, 0.85-0.98). Penicillin skin testing was temporally associated with lower hospital-acquired CDI rates (rate ratio, 0.61; 95% CI, 0.43-0.86). The embedded case-control study included 272 cases and 819 controls. Median age was 63 years (interquartile range, 51-73 years), 553 (50.7%) patients were women, and 229 (21.0%) patients were Black. Allergy-assessed patients were less likely to receive high-CDI-risk antibiotics at discharge (odds ratio, 0.66; 95% CI, 0.44-0.98). Estimated reductions in mortality (hazard ratio, 0.77; 95% CI, 0.55-1.07) and hospital-acquired CDI risk (hazard ratio, 0.53; 95% CI, 0.18-1.55) were not statistically significant.

CONCLUSIONS AND RELEVANCE

Pharmacist-led allergy assessments may be associated with reduced high-CDI-risk antibiotic use at both hospitalwide and individual levels. Although individual reductions in mortality and CDI risk did not achieve significance, divergence of survival curves suggest longer-term benefits of allergy delabeling warrant future study.

Short and long term impact of combining restrictive and enabling interventions to reduce aztreonam consumption in a community hospital

Background Antimicrobial stewardship initiatives combining restrictive and enabling components may be an effective strategy to achieve short- and long-term objectives. Aztreonam, a relatively high-cost antipseudomonal antibiotic, is an appropriate target for stewardship initiatives based on propensity for overuse in penicillin allergy, an activity profile often warranting additional empiric gram-negative and gram-positive coverage, and a unique durability to Ambler class B metallo-beta-lactamases. Objective Analyze the immediate and long-term impact on aztreonam prescribing of combining restrictive and enabling interventions. Setting Single 233-bed community hospital with 45 adult intensive care unit beds in Nashville, Tennessee. Method Retrospective, interrupted time series analysis comparing all patients receiving aztreonam prior to intervention between January 1, 2010 and September 30, 2011 and following intervention between October 1, 2011 and September 30, 2019. Quarterly defined daily doses/1000 adjusted patient days and microbiology laboratory annual surveillance data were utilized for analysis. Main outcome measure Post-intervention change in trend of aztreonam consumption. Results Following intervention, a significant decline in aztreonam consumption was observed (- 1.97 defined daily doses/1000 adjusted patient days; p = 0.003) resulting in a sustained decrease in aztreonam consumption from 2011 (3rd quarter) to 2019 (3rd quarter) from 15.2 to 0.26 defined daily doses/1000 adjusted patient days. Short-term group 2 carbapenem consumption increased (p = 0.044). Pseudomonas aeruginosa susceptibility to aztreonam improved from 2011 to 2018 (72% vs. 84%; p = 0.0004) without deleterious effects to alternative antipseudomonal beta-lactams. Conclusion Combining restrictive and enabling interventions had immediate and sustained impact on aztreonam consumption with P. aeruginosa susceptibility improvement.

Recent developments and highlights in drug hypersensitivity

Drug hypersensitivity reactions (DHRs) are nowadays the third cause of allergy after rhinitis and asthma with a significant increase in prevalence in both adults and paediatric population with new drugs included as culprit. For this, DHRs represent not only a health problem but also a significant financial burden for affected individuals and health systems. Mislabelling DHRs is showing to be a relevant problem for both, false label of drug allergic and false label of nonallergic. All this reinforces the need to improve accurate diagnostic approaches that allow an appropriate management. Moreover, there is a need for training both, nonallergist stakeholders and patients to improve the reaction identification and therefore decrease the mislabelling. The use of allergy cards has shown to be relevant to avoid the induction of DHRs due to the prescription of wrong medication. Recent developments over the last 2 years and highlights about risk factors, diagnostic approaches, mechanisms involved as well as prevention actions, and management have been reviewed. In these papers, it has been outlined the need for correct diagnosis and de-labelling of patients previously false-reported as allergic, which will improve the management and treatment of patients with DHRs.

Strategies for Clarifying Penicillin Allergies When Skin Testing Is Not an Option

Patients with reported penicillin allergies have been proven to experience negative health consequences, such as increased cost, suboptimal antimicrobial therapy, and adverse reactions. Though skin testing has been proposed as a method to clarify penicillin allergies, many institutions may lack the resources to perform skin testing on a wide scale. This literature review describes the current literature surrounding the use of penicillin allergy interviews when skin testing is not an option. Specifically, the review highlights the steps in carrying out a successful antibiotic allergy patient interview, summarizes the clinical evidence surrounding antibiotic allergy clarifications, and addresses key advantages and disadvantages of clarifying antibiotic allergies without the availability of skin testing.

Inpatient β-lactam test-dose protocol and antimicrobial stewardship in patients with a history of penicillin allergy

BACKGROUND

Penicillin allergy is the most commonly reported drug allergy in hospitalized patients, resulting in increased second-line antibiotic use, nosocomial infections, and health care use. Given that most patients are not truly allergic, a safe strategy that empowers the admitting physician is needed.

OBJECTIVE

To assess the effect on antibiotic prescribing practices for hospitalized patients with penicillin allergy using a validated intervention.

METHODS

An intervention was implemented to educate health care professionals on management of patients with penicillin allergy using a validated risk stratification algorithm to guide testing and antibiotic use. Thirty days of control data using current standard of care was compared with 60 days of postintervention data measuring documentation of penicillin allergy history and antibiotic selection.

RESULTS

The relative use of cephalosporin and penicillin antibiotics increased by 121.2% (P = .03) and 256% (P = .04), respectively, without an increase in adverse drug reactions. There was a decrease in the use of broad-spectrum antibiotics: vancomycin, 67.2% (P = .04); quinolones, 33.3% (P = .31); carbapenems, 81.9% (P = .08); and aztreonam, 73.8% (P = .18).

CONCLUSION

The antibiotic choice in patients admitted to the hospital with a reported penicillin allergy can be improved by better evaluation of the allergy history and the use of a risk stratification guideline.