Implementation of a penicillin allergy screening tool to optimize aztreonam use

A novel 2-step process for the management of inpatient beta-lactam allergy labels

BACKGROUND

Inpatient beta-lactam allergy labels may increase the unnecessary use of aztreonam and non-beta-lactam antibiotics, which can then lead to more adverse events and increased health care costs, OBJECTIVE: To assess the impact of a novel 2-step process (medication history review followed by risk stratification) on rates of beta-lactam delabeling, aztreonam use, and desensitizations on pediatric, adult, and obstetrics inpatients at a tertiary academic center.

METHODS

We prospectively collected data on 700 patients who received inpatient consultation from the Beta-Lactam Allergy Evaluation Service between August 2021 and July 2022. Patients were delabeled either by medication review alone, drug challenge alone if with a low-risk history, or penicillin skin test followed by drug challenge if with a high-risk history. Generalized linear regression modeling was used to compare aztreonam days of therapy in the intervention year with the 2 prior years. Drug desensitizations were assessed by electronic chart review.

RESULTS

Most of the patients (n = 656 of 700, 94%) had more than or equal to 1 beta-lactam allergy label removed, clarified, or both; 77.9% of these patients (n = 511 of 656) had 587 beta-lactam allergy labels removed. Nearly one-third (n = 149, 27.6%) had 162 allergy labels removed solely by medication history review. All 114 penicillin skin tests performed had negative results, and 98% (8 of 381) of the patients who underwent any drug challenge passed. Only 5.7% of the delabeled patients were relabeled. There was a 27% reduction in aztreonam use (P = .007). Beta-lactam desensitizations were reduced by 80%.

CONCLUSION

A full-time inpatient beta-lactam allergy service using medication history review and risk stratification can safely and effectively remove inpatient beta-lactam allergy labels, reduce aztreonam use, and decrease beta-lactam desensitizations.

Penicillin Allergy Impact and Management

There is international evidence that penicillin allergies are associated with inferior prescribing and patient outcomes. A host of tools now exist from assessment (risk assessment tools, clinical decision rules) to delabeling (the removal of a beta-lactam allergy via testing or medical reconciliation) to reduce the impact of these "labels" in the hospital and community setting, as a primary antimicrobial stewardship intervention.

Impact of an Inpatient Allergy Guideline on β-Lactam and Alternative Antibiotic Use

BACKGROUND

A guideline identifying when inpatients with penicillin or cephalosporin antibiotic allergy labels (PCAAL) can receive β-lactam antibiotics increased β-lactam receipt at a large northeastern US health care system.

OBJECTIVE

To report outcomes of implementing a similar guideline and electronic order set (OS) at an independent academic health care system.

METHODS

Penicillin/cephalosporin receipt (percentage of inpatients receiving full doses) and alternative antibiotic use (days of therapy per 1000 patient-days [DOT/1000PD]) were compared over 3 periods before (February 1, 2017, to January 31, 2018) and after guideline implementation (February 1, 2018, to January 31, 2019), and after OS implementation (February 1, 2019, to January 31, 2020) among inpatients with PCAAL admitted on medical services with access to guideline/OS and education (Medical-PCAAL, n = 8721), surgical services with access to guideline/OS without education (Surgical-PCAAL, n = 5069), and obstetrics/gynecology services without interventions (Ob/Gyn-PCAAL, n = 798) and inpatients without PCAAL admitted on the same services (Medical-No-PCAAL, n = 50,840; Surgical-No-PCAAL, n = 29,845; Ob/Gyn-No-PCAAL, n = 6109). χ2 tests were used to compare categorical variables, and analysis of variance was used to compare continuous and interrupted time series analyses (ITSA) to investigate the guideline/OS implementation effect on penicillin/cephalosporin receipt.

RESULTS

In the Medical-PCAAL group, penicillin/cephalosporin receipt increased (58%-68%, P < .001), specifically for cefazolin (8%-11%, P = .02) and third- to fifth-generation cephalosporins (43%-48%, P = .04), and aztreonam use decreased (12 DOT/1000PD, P = .03). In the Medical-No-PCAAL group, penicillin/cephalosporin receipt increased (88%-90%, P = .004), specifically for penicillin (40%-44%, P < .001), without changes in aztreonam use. Significant changes were not observed in these outcomes on surgical or obstetrics/gynecology services. Per ITSA, guideline/OS implementation was associated with increased penicillin/cephalosporin receipt in the Medical-PCAAL group only.

CONCLUSION

Guideline and OS implementation was associated with improved antibiotic stewardship on inpatient services that also received allergy education.

Penicillin allergy delabeling: Opportunities for implementation and dissemination

Although existing as a safety measure to prevent iatrogenic harm, unconfirmed penicillin allergy labels have a negative impact on personal and public health. One downstream effect of unconfirmed penicillin allergy is the continued emergence and transmission of resistant bacteria and their associated health care costs. Recognizing the consequences of inaccurate penicillin allergy labels, professional and public health organizations have started promoting the adoption of proactive penicillin allergy evaluations, with the ultimate goal of removing the penicillin allergy label when the allergy is disproved, also known as penicillin allergy "delabeling." A penicillin allergy evaluation includes a comprehensive allergy history often followed by drug challenge, sometimes with preceding skin testing. Currently, penicillin allergy delabeling is largely carried out by allergy specialists in outpatient settings. Penicillin allergy delabeling is performed on inpatients, albeit rarely, often at the time of need, as a point-of-care procedure. Access to penicillin allergy evaluation services is limited. Recent studies demonstrate the feasibility of expanding penicillin allergy evaluations and delabeling to internists, pediatricians, emergency medicine physicians, infectious diseases specialists, and clinical pharmacists. However, reducing the impact of mislabeled penicillin allergy will require comprehensive efforts and new investments. In this review, we summarize the current practices of penicillin allergy delabeling and discuss expansion opportunities for penicillin allergy delabeling as quality improvement.

Drug Allergy Delabeling Programs: Recent Strategies and Targeted Populations

Drug allergy delabeling programs have become an essential element of antibiotic stewardship. Development of delabeling programs involves careful selection of target patient population, thoughtful design of delabeling approach, stakeholder engagement, assembly of key team members, implementation, and evaluation of clinical and safety outcomes. Recent programs have targeted patients thought to be most likely to benefit from removal of inaccurate antibiotic allergy labels, those with β-lactam antibiotic allergies and high-risk populations likely to need β-lactam antibiotics as first-line treatment. This review provides an overview of current risk stratification methods and β-lactam cross-reactivity data and summarizes how different inpatient and outpatient delabeling programs have used these concepts in delabeling algorithms. β-Lactam delabeling programs for inpatients, pediatric patients, and programs utilizing telehealth have been implemented with good outcomes. This review also focuses on delabeling programs for high-risk populations likely to benefit from first-line β-lactam antibiotics. These populations include perioperative, prenatal, and immunocompromised patients. Delabeling programs have been successful in the inpatient and outpatient settings at enabling appropriate antibiotic use. This article reviews delabeling strategies utilized by these programs with a focus on highlighting elements key to their success and future areas for innovation.

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.

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

BACKGROUND

The WHO's AWaRe classification categorizes antibiotics into three stewardship groups: Access, Watch and Reserve. The Access group includes antibiotics with lower resistance potential than antibiotics in the other two groups. The UK five-year AMR strategy has set targets for reducing non-Access antibiotic use. The majority of penicillins are in the Access group and therefore patients with a penicillin allergy record are likely to receive more non-Access antibiotics. This study aimed to quantify the impact of penicillin allergy records on non-Access antibiotic prescribing and to estimate potential reductions in non-Access antibiotic use through penicillin allergy de-labelling.

METHODS

Inpatients of a 750-patient-bed UK district general hospital in England prescribed antibiotics between 1^st April 2018 and 31^st March 2019 were included. Variables included: age, sex, co-morbidity, infection treated, antibiotic usage, hospital length of stay, penicillin allergy status. Multivariable logistic regression was used to explore the association between patient characteristics and their receipt of antibiotics in the Access and non-Access groups.

RESULTS

A total of 67,059 antibiotic prescriptions for 23,356 inpatients were analysed. Penicillin allergy records were present in 14.3% of hospital admissions. Patients with a penicillin allergy record were around four times more likely (odds ratio = 4.7) to receive an antibiotic from the non-Access groups (i.e. Reserve and Watch groups). We estimate de-labelling 50% of hospital inpatients with a penicillin allergy record could reduce non-Access antibiotic use by 5.8% and total antibiotic use by 0.86%.

CONCLUSION

Penicillin allergy records are associated with non-Access antibiotic prescribing. Penicillin allergy de-labelling has potential to reduce non-Access antibiotic use.

Inappropriate Use of Aztreonam

BACKGROUND

Aztreonam is not a preferred empiric antibiotic because of variable susceptibilities compared with alternative agents. In addition, it has no Gram-positive activity, necessitating coadministration with vancomycin when used empirically, and is more costly when compared with other Gram-negative active agents. Aztreonam is often given to patients with a reported penicillin allergy without further investigation into the reaction or other relevant allergy information.

STUDY QUESTION

How frequently is aztreonam being used inappropriately?

STUDY DESIGN

We conducted a retrospective chart review at an academic medical center to assess the appropriateness of our aztreonam use.

MEASURES AND OUTCOMES

Our primary outcome was frequency of appropriate aztreonam use, based on a true IgE-mediated allergy reported for each patient. We evaluated whether the patients had tolerated a beta-lactam in the past, and what the reported allergic reaction was.

RESULTS

We included 165 patients and found that 46.7% of our aztreonam use was inappropriate, based on previous use of a beta-lactam, or no documentation of an IgE-mediated response. Of the patients with a documented beta-lactam allergy, 63 (38.2%) patients had no allergy manifestation listed, and 37 (22.4%) patients had a non-IgE-mediated allergy manifestation. Of the total population, 61 (37%) patients had tolerated a beta-lactam in the past.

CONCLUSIONS

Aztreonam should be avoided, except in the case of a true IgE-mediated allergic reaction. Our goal was to reduce the inappropriate use of aztreonam at our institution by one or more of the following: educating providers, reviewing aztreonam orders, requiring answering of order questions, or requiring an indication for use. Penicillin skin testing and desensitization are options as well.

The challenge of de-labeling penicillin allergy

BACKGROUND

Even though 8%-25% of most populations studied globally are labeled as penicillin allergic, most diagnoses of penicillin allergy are made in childhood and relate to events that are either not allergic in nature, are low risk for immediate hypersensitivity, or are a potential true allergy that has waned over time. Penicillin allergy labels directly impact antimicrobial stewardship by leading to use of less effective and broader spectrum antimicrobials and are associated with antimicrobial resistance. They may also delay appropriate antimicrobial therapy and lead to increased risk of specific adverse healthcare outcomes. Operationalizing penicillin allergy de-labeling into a new arm of antimicrobial stewardship programs (ASPs) has become an increasing global focus.

METHODS

We performed an evidence-based narrative review of the literature of penicillin allergy label carriage, the adverse effects of penicillin allergy labels, and current approaches and barriers to penicillin allergy de-labeling. Over the period 1928-2018 in Pubmed and Medline, search terms used included "penicillin allergy" or "penicillin hypersensitivity" alone or in combination with "adverse events," "testing," "evaluation," "effects," "label," "de-labeling," "prick or epicutaneous," and "intradermal" skin testing, "oral challenge or provocation," "cross-reactivity," and "antimicrobial stewardship".

RESULTS

Penicillin allergy labels are highly prevalent, largely inaccurate and their carriage may lead to unnecessary treatment and inferior outcomes with alternative agents as well as adverse public health outcomes such as antibiotic resistance.

CONCLUSIONS

Operationalizing penicillin allergy de-labeling as an aspect of ASP has become an increasing global focus. There is a need for validated approaches that optimally combine the use of history and ingestion challenge with or without proceeding formal skin testing to tackle penicillin allergy efficiently within complex healthcare systems. At the same time, there is great promise for penicillin allergy evaluation and de-labeling as an individual and public health strategy to reduce adverse healthcare outcomes, improve antimicrobial stewardship, and decrease healthcare costs.

Implementation of a Pharmacist-Driven Detailed Penicillin Allergy Interview

Background: Self-reported penicillin allergies may be outdated or inaccurate, leading to the use of alternative antimicrobials that may be less effective, more toxic, and/or more expensive. Although penicillin skin tests can provide accurate assessments of penicillin allergies, these procedures are not feasible at all institutions. Another solution is to conduct a detailed penicillin allergy interview (DPAI), which can potentially lead to optimization of antimicrobial therapy. Objective: The purpose of this study was to assess the impact of a pharmacist-driven DPAI protocol. The primary objective was to measure the number of patients requiring a change to their allergy profile following DPAI. Secondary objectives included characterizing allergy profile updates and measuring the number of recommendations to switch to a β-lactam agent, provider acceptance rate, and patient tolerance. Methods: Standardized pharmacist-driven DPAIs were conducted prospectively on adult patients admitted with a documented penicillin allergy. The allergy profile within the electronic health record (EHR) was updated and a recommendation to switch to noncarbapenem β-lactam therapy was made when indicated by a decision algorithm. Results: A total of 175 (37.5%) patients received a DPAI. Of these, 133 (76.0%) required a change to their allergy profile. Additionally, 135 (77.1%) patients interviewed were on antimicrobial therapy, with 42 (31.1%) meeting criteria to switch to noncarbapenem β-lactam therapy; of which 31 (73.8%) patients were successfully transitioned, with no signs or symptoms of intolerance. Conclusions and Relevance: Implementation of pharmacist-driven DPAIs can provide updated and corrected allergy information within the EHR, allowing for de-escalation and/or optimization of antimicrobial therapy.

Antibiotic misuse: How to evaluate the costs?

OBJECTIVE

Few studies have assessed the costs associated with the misuse of antibiotics in hospitals in France, despite the value of health economic data to inform antibiotic stewardship activities. We aimed to identify the methodological tools used to assess the cost of antibiotic misuse in hospitals.

METHODS

We performed a literature review using the major electronic medical databases. An index of relevance was developed to assess the intrinsic quality of selected articles.

RESULTS

Four hundred and three articles were retrieved, but 35 were selected for analysis. Most studies investigated the inadequate choice of the antibiotic molecule (n=17), the incorrect treatment duration (n=9), and the administration of an inappropriate dosage (n=7). Only three studies were medical/economic evaluations of specific interventions, such as prescription control by pharmacists or the implementation of a new diagnostic test. Considering our aim, the relevance of the studies was limited: few had defined the economic assessment as the primary objective or had detailed the method for calculating costs. Nevertheless, the misuse evaluation was usually better described.

CONCLUSIONS

Despite these limits, key factors for measuring antibiotic misuse (i.e., molecule choice, dosage) in relation to the costs (i.e., over/under prescription, hospital stay, staff remuneration) might serve as the basis for the development of a reference methodology to value the costs of misuse. The application of this methodology on identified situations of antibiotic misuse would help hospital decision-makers to justify resource allocation for implementing antimicrobial stewardship activities.

Outcomes from an inpatient beta-lactam allergy guideline across a large US health system

Objective:

To assess the safety of, and subsequent allergy documentation associated with, an antimicrobial stewardship intervention consisting of test-dose challenge procedures prompted by an electronic guideline for hospitalized patients with reported β-lactam allergies.

Design:

Retrospective cohort study.

Setting:

Large healthcare system consisting of 2 academic and 3 community acute-care hospitals between April 2016 and December 2017.

Methods:

We evaluated β-lactam antibiotic test-dose outcomes, including adverse drug reactions (ADRs), hypersensitivity reactions (HSRs), and electronic health record (EHR) allergy record updates. HSR predictors were examined using a multivariable logistic regression model. Modification of the EHR allergy record after test doses considered relevant allergy entries added, deleted, and/or specified.

Results:

We identified 1,046 test-doses: 809 (77%) to cephalosporins, 148 (14%) to penicillins, and 89 (9%) to carbapenems. Overall, 78 patients (7.5%; 95% confidence interval [CI], 5.9%–9.2%) had signs or symptoms of an ADR, and 40 (3.8%; 95% CI, 2.8%–5.2%) had confirmed HSRs. Most HSRs occurred at the second (ie, full-dose) step (68%) and required no treatment beyond drug discontinuation (58%); 3 HSR patients were treated with intramuscular epinephrine. Reported cephalosporin allergy history was associated with an increased odds of HSR (odds ratio [OR], 2.96; 95% CI, 1.34–6.58). Allergies were updated for 474 patients (45%), with records specified (82%), deleted (16%), and added (8%).

Conclusion:

This antimicrobial stewardship intervention using β-lactam test-dose procedures was safe. Overall, 3.8% of patients with β-lactam allergy histories had an HSR; cephalosporin allergy histories conferred a 3-fold increased risk. Encouraging EHR documentation might improve this safe, effective, and practical acute-care antibiotic stewardship tool.

Controversies in Drug Allergy: Drug Allergy Pathways

Drug allergy pathways are standardized approaches for patients reporting prior drug allergies with the aim of quality improvement and promotion of antibiotic stewardship. At the International Drug Allergy Symposium during the 2018 American Academy of Allergy, Asthma, and Immunology/World Allergy Organization Joint Congress in Orlando, Florida, drug allergy pathways were discussed from international perspectives with a focus on beta-lactam allergy pathways and pragmatic approaches for acute care hospitals. In this expert consensus document, we review current pathways, and detail important considerations in devising, implementing, and evaluating beta-lactam allergy pathways for hospitalized patients. We describe the key patient and institutional factors that must be considered in risk stratification, the central feature of pathway design. We detail shared obstacles to widespread beta-lactam allergy pathway implementation and identify potential solutions to address these challenges.

Improving Aztreonam Stewardship and Cost Through a Penicillin Allergy Testing Clinical Guideline

Background

Patients reporting penicillin allergy often receive unnecessary and costly broad-spectrum alternatives such as aztreonam with negative consequences. Penicillin allergy testing improves antimicrobial therapy but is not broadly used in hospitals due to insufficient testing resources and short-term expenses. We describe a clinical decision support (CDS) tool promoting pharmacist-administered penicillin allergy testing in patients receiving aztreonam and its benefits toward antimicrobial stewardship and costs.

Methods

A CDS tool was incorporated into the electronic medical record, directing providers to order penicillin allergy testing for patients receiving aztreonam. An allergy-trained pharmacist reviewed orders placed through this new guideline and performed skin testing and oral challenges to determine whether these patients could safely take penicillin. Data on tests performed, antibiotic utilization, and cost-savings were compared with patients tested outside the new guideline as part of our institution's standard stewardship program.

Results

The guideline significantly increased penicillin allergy testing among patients receiving aztreonam from 24% to 85% (P < .001) while reducing the median delay between admission and testing completion from 3.31 to 1.05 days (P = 0.008). Patients tested under the guideline saw a 58% increase in penicillin exposure (P = .046). Institutional aztreonam administration declined from 2.54 to 1.47 administrations per 1000 patient-days (P = .016). Average antibiotic costs per patient tested before and after CDS decreased from $1265.81 to $592.08 USD, a 53% savings.

Conclusions

Targeting penicillin allergy testing to patients on aztreonam yields therapeutic and economic benefits during a single admission. This provides a cost-effective model for inpatient testing.

Impact of a Standardized Beta-Lactam Allergy Questionnaire on Aztreonam Use

METHODS

This quasi-experimental study compared the aztreonam utilization in patients with self-reported beta-lactam allergies admitted to an inpatient service between two study periods (pre- and post-implementation). Post-implementation followed the initiation of a standardized beta-lactam allergy questionnaire, a student pharmacist-driven performance improvement project for beta-lactam allergy documentation. Interviews clarified the allergy, reaction history, and any previous tolerance of beta-lactams. If receiving aztreonam at the time of the questionnaire, recommendations were made for changes in therapy if deemed appropriate by the pharmacist.

RESULTS

A total of 95 patients were included in the pre-implementation group versus 65 patients in the post-implementation group. Baseline characteristics were similar. The average number of aztreonam doses per 1000 patient-days in the post-implementation group was decreased (21.23 vs 9.05, P = .003). The average number of days of therapy per 1000 patient-days in the post-implementation group was decreased (8.79-4.24, P = .016). An increase in the number of aztreonam de-escalations was observed post-implementation (P = .003). A total of 122 questionnaires were completed with 114 allergy documentation updates. There were no reported instances of adverse events.

CONCLUSION

Utilization of a standardized beta-lactam allergy questionnaire as a pharmacy education tool resulted in a statistically significant decrease in aztreonam utilization, based on doses, days of therapy, and de-escalations.

The Cost of Self-Reported Penicillin Allergy: A Systematic Review

BACKGROUND

Patients who report a penicillin (PCN) allergy receive suboptimal antibiotic therapy compared with patients not reporting an allergy. However, a majority of patients who report PCN allergy are not truly allergic on confirmatory testing. Ruling out PCN allergy by testing may improve clinical and economic outcomes for patients with reported allergies requiring antibiotic therapy.

OBJECTIVE

The objective of this study was to summarize clinical and economic outcomes associated with PCN allergy and provide recommendations for future cost-effectiveness analyses for PCN allergy testing.

METHODS

A literature search was conducted using SCOPUS, EMBASE, and PubMed, including all articles published any date through April 25, 2017 (PROSPERO Registration number 42017064112). A total of 1518 abstracts were found during the initial search with 96 duplicates, for a total of 1422 articles for screening. Thirty articles were included for qualitative synthesis and full data extraction.

RESULTS

The majority of the studies included had an observational design focusing on inpatient admissions. The most frequently measured outcome in the context of PCN allergy was optimizing antibiotic therapy. Patients with PCN allergy were found to have direct drug costs during inpatient admission ranging from no difference to an additional $609/patient compared with patients without PCN allergy. Outpatient prescription costs were estimated from $14 to $193/patient higher for PCN allergic patients. Total inpatient costs were less for patients without PCN allergy with average savings from $1145 to $4254/patient.

CONCLUSIONS

Evaluations of clinical and economic outcomes of PCN allergy are primarily observational and focus on inpatient populations. Long-term relationships between PCN allergy and clinical and economic outcomes are unknown.

Confronting the Challenge of Beta-Lactam Allergies: A Quasi-Experimental Study Assessing Impact of Pharmacy-Led Interventions

OBJECTIVE

To improve allergy history documentation and increase the use of beta-lactams when appropriate in patients with a reported beta-lactam allergy.

METHODS

This pre-post study was conducted at a 167-bed tertiary care community hospital and evaluated multidisciplinary interventions on allergy documentation and antibiotic selection. Interventions included education, creation of local practice guidelines, and modified practices for pharmacists and pharmacy technicians. Inpatients with a reported beta-lactam allergy receiving at least 1 antibiotic for >24 hours were included; first admissions were assessed. Primary outcomes were documentation of reaction type and percentage of patients receiving non-beta-lactam therapy. Secondary outcomes included documentation of previously tolerated beta-lactams, modification of non-beta-lactam therapy, discharge antibiotics, and adverse reactions.

RESULTS

A total of 179 patients were included, 91 preintervention and 88 postintervention. No significant differences were observed between the before versus after groups in the percentage of patients with documentation of reaction type (90.1% vs 89.8%, P = .940) or the overall percentage of patients receiving non-beta-lactams (86.8% vs 84.1%, P = .605). However, significantly more patients in the after phase had documentation of previously tolerated beta-lactams (8.8% vs 28.4%, P = .001), and among patients receiving a non-beta-lactam, a greater percentage was subsequently switched to a beta-lactam (11.4% vs 25.7%, P = .022). One allergic reaction was documented during the study, which occurred in the before phase.

CONCLUSION

Multidisciplinary education and local guideline implementation led by pharmacists may improve allergy documentation and antibiotic selection in patients with reported beta-lactam allergies.

The 3 Cs of Antibiotic Allergy-Classification, Cross-Reactivity, and Collaboration

Antibiotic allergy labeling is highly prevalent and negatively impacts patient outcomes and antibiotic appropriateness. Reducing the prevalence and burden of antibiotic allergies requires the engagement of key stakeholders such as allergists, immunologists, pharmacists, and infectious diseases physicians. To help address this burden of antibiotic allergy overlabeling, we review 3 key antibiotic allergy domains: (1) antibiotic allergy classification, (2) antibiotic cross-reactivity, and (3) multidisciplinary collaboration. We review the available evidence and research gaps of currently used adverse drug reaction classification systems, antibiotic allergy cross-reactivity, and current and future models of antibiotic allergy care.

The effectiveness of computerised decision support on antibiotic use in hospitals: A systematic review

Background

Inappropriate antimicrobial use has been shown to be an important determinant of the emergence of antimicrobial resistance (AMR). Health information technology (HIT) in the form of Computerised Decision Support (CDS) represents an option for improving antimicrobial prescribing and containing AMR.

Objectives

To evaluate the evidence for CDS in improving quantitative and qualitative measures of antibiotic prescribing in inpatient hospital settings.

Methods

A systematic literature search was conducted of articles published from inception to 20^th December 2014 using eight electronic databases: MEDLINE, EMBASE, PUBMED, Web of Science, CINAHL, Cochrane Library, HMIC and PsychINFo. An updated systematic literature search was conducted from January 1^st 2015 to October 1^st 2016 using PUBMED. The search strategy used combinations of the following terms: (electronic prescribing) OR (clinical decision support) AND (antibiotic or antibacterial or antimicrobial) AND (hospital or secondary care or inpatient). Studies were evaluated for quality using a 10-point rating scale.

Results

Eighty-one studies were identified matching the inclusion criteria. Seven outcome measures were evaluated: adequacy of antibiotic coverage, mortality, volume of antibiotic usage, length of stay, antibiotic cost, compliance with guidelines, antimicrobial resistance, and CDS implementation and uptake. Meta-analysis of pooled outcomes showed CDS significantly improved the adequacy of antibiotic coverage (n = 13; odds ratio [OR], 2.11 [95% CI, 1.67 to 2.66, p ≤ 0.00001]). Also, CDS was associated with marginally lowered mortality (n = 20; OR, 0.85 [CI, 0.75 to 0.96, p = 0.01]). CDS was associated with lower antibiotic utilisation, increased compliance with antibiotic guidelines and reductions in antimicrobial resistance. Conflicting effects of CDS on length of stay, antibiotic costs and system uptake were also noted.

Conclusions

CDS has the potential to improve the adequacy of antibiotic coverage and marginally decrease mortality in hospital-related settings.

Impact of an Integrated Antibiotic Allergy Testing Program on Antimicrobial Stewardship: A Multicenter Evaluation

Background

Despite the high prevalence of patient-reported antibiotic allergy (so-called antibiotic allergy labels [AALs]) and their impact on antibiotic prescribing, incorporation of antibiotic allergy testing (AAT) into antimicrobial stewardship (AMS) programs (AAT-AMS) is not widespread. We aimed to evaluate the impact of an AAT-AMS program on AAL prevalence, antibiotic usage, and appropriateness of prescribing.

Methods

AAT-AMS was implemented at two large Australian hospitals during a 14-month period beginning May 2015. Baseline demographics, AAL history, age-adjusted Charlson comorbidity index, infection history, and antibiotic usage for 12 months prior to testing (pre-AAT-AMS) and 3 months following testing (post-AAT-AMS) were recorded for each participant. Study outcomes included the proportion of patients who were "de-labeled" of their AAL, spectrum of antibiotic courses pre- and post-AAT-AMS, and antibiotic appropriateness (using standard definitions).

Results

From the 118 antibiotic allergy-tested patients, 226 AALs were reported (mean, 1.91/patient), with 53.6% involving 1 or more penicillin class drug. AAT-AMS allowed AAL de-labeling in 98 (83%) patients-56% (55/98) with all AALs removed. Post-AAT, prescribing of narrow-spectrum penicillins was more likely (adjusted odds ratio [aOR], 2.81, 95% confidence interval [CI], 1.45-5.42), as was narrow-spectrum β-lactams (aOR, 3.54; 95% CI, 1.98-6.33), and appropriate antibiotics (aOR, 12.27; 95% CI, 5.00-30.09); and less likely for restricted antibiotics (aOR, 0.16; 95% CI, .09-.29), after adjusting for indication, Charlson comorbidity index, and care setting.

Conclusions

An integrated AAT-AMS program was effective in both de-labeling of AALs and promotion of improved antibiotic usage and appropriateness, supporting the routine incorporation of AAT into AMS programs.