The prevalence of suspected and challenge-verified penicillin allergy in a university hospital population

Preoperative survey to evaluate the patients' allergy list and its relevance to perioperative care

INTRODUCTION

Perioperative hypersensitivity and allergic reactions can result in significant morbidity and mortality. For routine anesthetic care, allergies are determined from a review of the electronic medical record supplemented by a detailed patient history. Although the electronic medical record is generally assumed to be accurate, it may be that allergies are erroneously listed or not based on sound medical practice. The purpose of the current study is to evaluate allergies listed in the electronic medical record of children presenting for surgery and determine their origin, authenticity, and impact on perioperative care.

METHODS

Eligible patients included those presenting for a surgical procedure in the main operating room, who were ≤ 21 years of age, with a drug allergy listed on the EMR. Prior to intraoperative care, an electronic survey questionnaire containing questions related to medication allergies was provided to a guardian or parent. Two anesthesiology physicians reviewed the survey responses to determine the validity of any reported allergies. A second electronic survey was given postoperatively to the attending anesthesiologist to determine whether the documented allergy impacted anesthetic care.

RESULTS

The study cohort included 250 patients, ranging in age from 5 to 14 years (median age 9 years). All of the patients had at least one allergy listed on the electronic medical record. Seventy of the 250 patients (28%) had more than one drug allergy listed for a total of 351 medication allergies. The majority of the listed allergies were related to antibiotics including 155 (44%) from the penicillin family, 26 (7%) cephalosporins, 16 (5%) sulfonamides, and 36 (10%) other antimicrobial agents. Other commonly listed allergies were 27 (8%) nonsteroidal anti-inflammatory agents and 15 (4%) opioids. The remaining 76 (22%) included a miscellaneous list of other medications. On further review of the allergies, the survey was completed for 301 medications. After physician review, 135 of 301 (45%) responses were considered consistent with IgE reactions "true allergy," 73 (24%) were deemed less relevant to IgE reactions "unlikely true allergy," and 93 (31%) were not related to IgE reactions "not an allergy." Care alterations during surgery were uncommon regardless of whether the issue was assessed as a true allergy (11%), unlikely to be a true allergy (3%), or not a true allergy (13%).

CONCLUSION

A significant portion of the documented allergies in children are not true allergies, but rather recognized adverse effects (apnea from an opioid, renal failure from an NSAIDs) or other nonallergic concerns (gastrointestinal upset such as nausea). Erroneously listed allergies may lead to unnecessary alterations in patient care during perioperative care. A careful analysis of the allergy list on the EMR should be supplemented by a thorough patient history with specific questions related to the drug allergy. Once this is accomplished, the allergy listed should be updated to avoid its erroneous impact on perioperative care.

[Precision medicine in infectious diseases]

Infectious medicine faces a variety of challenges, such as the increase in antibiotic resistance and the emergence and spread of infectious diseases fueled by climate change and globalization. Precision medicine can provide solutions to many of these challenges. Since an untargeted request for diagnostic tests can lead to test results without clinical relevance, which can increase the use of non-indicated antibiotics, the principle aimed at is: targeted diagnostics (the right test) and consideration of patient characteristics (the right person) to optimize management (the right action). At the same time, one must always decide whether empirical therapy must be immediately initiated, even if the results of the initiated diagnostics are not yet available. In addition, many new diagnostics as well as therapies have recently been developed for the rapid detection and more specific treatment of bacterial infections. Molecular genetic methods, which offer more rapid results than classical bacterial cultures, are gaining ground as new diagnostics. New therapeutics such as bacteriophages, antibodies or antibacterial peptides allow increasingly precise treatment of certain bacterial infections. Precision medicine will also play an increasingly important role in infectious medicine in the future.

Assessing Pediatric Cephalosporin Allergic Reactions Through Direct Graded Oral Challenges

BACKGROUND

Cephalosporins, β-lactam antibiotics, commonly cause allergic reactions.

OBJECTIVE

To assess the clinical characteristics and management of pediatric patients with suspected cephalosporin allergy using direct graded oral challenges (GOCs).

METHODS

Children referred for suspected cephalosporin allergy at 4 Canadian clinics were recruited over 10 years. Data on demographics, clinical reaction characteristics, and management were collected through a questionnaire. Patients underwent a direct GOC (initially 10% of the treatment dose, then 90% after 20 min), and reactions were monitored 1 week postchallenge. Families were contacted annually for up to 5 years to detect subsequent antibiotic reactions. Logistic regression analysis identified factors associated with positive GOC reactions.

RESULTS

Among the 136 patients reporting cephalosporin allergy, 75 (55.1%) were males with a median age of 3.9 years (interquartile range 2.3-8.7). Cefprozil represented the most common cephalosporin linked to the index reaction (67.6% of cases). Of the 136 direct GOCs, 5.1% had an immediate and 4.4% a nonimmediate reaction, respectively. Positive GOCs conducted in children with a history of skin-limited nonsevere rashes were classified as mild, benign skin rashes. Positive GOCs were more likely in children with food allergies (adjusted odds ratio 1.14; 95% confidence interval [95% CI] 1.00-1.29).

CONCLUSIONS

Direct GOCs are safe and effective for diagnosing pediatric cases that report nonvesicular skin-limited symptoms while being treated with cephalosporins.

Assessing delayed penicillin hypersensitivity using the PENFAST+ score

Introduction

Approximately 10% of individuals report a suspected allergy to penicillin, but according to allergy work-ups, only 10%-15% of them are truly allergic. A clinical decision score, the PEN-FAST, was developed and validated to identify adults with low-risk penicillin allergy.

Objectives

The objective of this study was to improve the performance of the PEN-FAST score, particularly for those with delayed hypersensitivity (HS), by improving the negative predictive value.

Methods

STEP 1: Retrospective evaluation of the PEN-FAST score in patients with proven immediate and delayed penicillin allergy. STEP 2: Identification of additional criteria among Step 1 patients misclassified by PEN-FAST score. Development of the PEN-FAST+ score using multivariable logistic regression in a prospective cohort of patients with a suspicion of HS to penicillin. STEP 3: Comparison of diagnostic performances of PEN-FAST and PEN-FAST+ scores.

Results

The PEN-FAST score showed limitations in predicting the relapse of immediate skin HS or delayed maculopapular exanthema, with 28.6% and 38.4% of patients misclassified, respectively. We identified two potential additional criteria: skin rash lasting more than 7 days and immediate reaction occurring in less than 1 h (generalized or localized on palmoplantar area or scalp itching/heat feeling). A total of 32/252 (12.7%) patients were confirmed to be allergic to penicillin. With PEN-FAST, 37% of patients (n = 10) with delayed allergic penicillin HS were misclassified. With PEN-FAST+, 3 patients with delayed HS confirmed by a ST (11.1%) were misclassified. The AUC was significantly higher for PEN-FAST+ than PEN-FAST (85% vs. 72%, p = 0.03).

Penicillin allergy that persisted after 66 years: case report

The most common documented allergy is due to penicillin use, and penicillin allergy is often diagnosed early in childhood. However, fewer than 1% of the approximately 10% of the population with reported penicillin allergy have a true allergy. Antimicrobial stewardship programmes have employed pharmacist-led protocols to rechallenge patients with a documented history of penicillin allergy. There are published data to suggest that patients with a history of penicillin allergy can be successfully rechallenged and desensitised. We report a case of a 74-year-old woman with a documented childhood history of penicillin allergy who was rechallenged with amoxicillin/clavulanate (Augmentin) in the hospital during admission. She was given one trial dose of amoxicillin/clavulanate for the treatment of urinary tract infection to cover organisms detected in the urine culture. Amoxicillin/clavulanate was determined to be the most suitable antibiotic for empirical treatment. Given a documented history of penicillin allergy from over 60 years ago, the likelihood of reactivity was suspected to be low to none. The patient, however, developed an allergic reaction after the one-time oral amoxicillin/clavulanate 875/125 mg dose trial.

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.

Delabeling of Penicillin Allergy: Room for Improvement

BACKGROUND

Penicillin allergy labels have been shown to be associated with suboptimal treatment, negative health outcomes, and increased antibiotic resistance. Many inpatients claim to have penicillin allergy, but studies show that allergy can be disproved and the label removed in up to 90% of cases.

OBJECTIVES

The purpose of the study was to investigate the proportion of patients with a penicillin allergy label in a Danish hospital and to classify patients according to the risk of having penicillin allergy in "no risk," low, and high risk.

METHODS

For 22 days, inpatients with penicillin allergy labels were interviewed, had their dispensed penicillin prescriptions examined, and were subsequently categorized into risk groups based on the risk evaluation criteria in national guidelines.

RESULTS

In total, 260 patients had a penicillin allergy label (10% of the inpatients). Out of 151 included patients, 25 were "no risk" patients (17%), who could potentially have their penicillin allergy label removed without testing. 42 were low-risk patients (28%). 10 "no risk" patients and 20 low-risk patients had been prescribed and dispensed one or more penicillins despite an allergy label.

CONCLUSION

Ten percent of inpatients have a penicillin allergy label in a Danish hospital. 17% of these could potentially have their penicillin allergy label removed without allergy testing.

[Drug allergy: Fundamental aspects in diagnosis and treatment.]

BACKGROUND

Any substance used as a treatment for any disease can produce harmful or unpleasant events called adverse drug reactions (ADRs). They are due to inherent biological effects of the drug and are caused by immunological and non-immunological mechanisms.

OBJECTIVES

To describe the immunological mechanisms of hypersensitivity reactions (HSR) to drugs, their epidemiology, risk factors, classification, clinical manifestations, diagnosis, treatment, and prognosis.

METHODS

A review of the most current literature in English and Spanish was carried out, in the main databases, related to the HSR of various drug groups.

RESULTS

This study describes the terms used to define ADRs and HSRs, their classification and clinical manifestations, current diagnostic tools, treatment algorithms and prognosis of the most frequently used medications and with the highest prevalence of reported adverse events.

CONCLUSION

ADRs are a challenging entity, with a complex pathophysiology that has not been fully understood. Its approach requires a careful consideration since not all drugs have validated tests for their diagnosis nor a specific treatment. When indicating the use of any drug, the severity of the disease, the availability of other treatments and the potential risks of developing future adverse events should always be taken into consideration.

[allergy to penicillin - no beta-lactam antibiotics?]

Drug allergies are frequently reported by patients undergoing pre-anesthesia evaluation, potentially resulting in a suboptimal treatment with alternative substances. While about 10% of patients report to be allergic to penicillin, less than 1% have a true IgE-mediated allergy. Multiple factors contribute to this large prevalence, such as misinterpretations of common gastrointestinal side effects as “allergic”, a history of penicillin treatment for infectious mononucleosis resulting in skin rashes, uncritical acceptance of the diagnosis by medical staff or neglect to the fact that most patients will lose their sensitivity after 10 years. In addition to this, cephalosporins are regularly withheld from patients with penicillin allergy due to an unwarranted fear of cross-reactivity. Therefore, a correct identification of those in which penicillins or cephalosporins are truly contraindicated is paramount to avoid an unnecessary use of antibiotics with a less favorable spectrum.

Outcome of preoperative cefazolin use for infection prophylaxis in patients with self-reported penicillin allergy

BACKGROUND

Cephalosporins are the preferred antibiotics for prophylaxis against surgical site infections. Most studies give a rate of combined IgE and non-IgE penicillin allergy yet it is recommended that cephalosporins be avoided in patients having the former but can be used in those with the latter. Some studies use penicillin allergy while others penicillin family allergy rates. The primary goal of this study was to determine the rates of IgE and non-IgE allergy as well as cross reactions to both penicillin and the penicillin family. Secondary goals were to determine the surgical services giving preoperative cefazolin and the types of self reported reactions that patients' had to penicillin prompting their allergy status.

METHODS

All patients undergoing elective and emergency surgery at a University Health Sciences Centre were retrospectively studied. The hospital electronic medical record was used for data collection.

RESULTS

8.9% of our patients reported non-IgE reactions to penicillin with a cross reactivity rate of 0.9% with cefazolin. 4.0% of our patients reported IgE reactions to penicillin with a cross reactivity rate of 4.0% with cefazolin. 10.5% of our patients reported non-IgE reactions to the penicillin family with a cross reactivity rate of 0.8% with cefazolin. 4.3% of our patients reported IgE reactions to the penicillin family with a cross reactivity rate of 4.0% with cefazolin.

CONCLUSIONS

Our rate of combined IgE and non-IgE reactions for both penicillin and penicillin family allergy was within the range reported in the literature. Our rate of cross reactivity between cefazolin and combined IgE and non-IgE allergy both to penicillin and the penicillin family were lower than reported in the old literature but within the range of the newer literature. We found a lower rate of allergic reaction to a cephalosporin than reported in the literature. We documented a wide range of IgE and non-IgE reactions. We also demonstrated that cefazolin is frequently the preferred antibiotics for prophylaxis against surgical site infections by many surgical services and that de-labelling patients with penicillin allergy is unnecessary.

[Efficiency of the allergological study in the diagnosis of allergic reactions to beta-lactams]

AIMS

Assessing the rate of β-lactams-allergic patients who are still labelled as such in their medical records after being performed an allergic test; as well as the rate of no allergic patients who were prescribed one of these antibiotics; and pondering whether the allergic test is hence cost-effective.

METHODS

This is a retrospective study developed from 2019 to 2021 focusing on patients suspected of β-lactams allergy (n=688). By means of an allergy test, it was cleared out if they were actually allergic. Later, we checked if the patient was still labelled as allergic in their medical record. Tracking through the digital health services card, we followed up if the antibiotic was ever prescribed again, and if the drug was then dispensed to the patient.

RESULTS

11.3% of the patients showed hypersensitivity to β-lactams. Nonetheless, 33.1% of the patients were still considered allergic to these antibiotics in their medical record even though not being such. 32% of the patients - who had their allergy confirmed - had been labelled without the general practitioner's acknowledgment, and 32.8% had even been prescribed a β-lactam again.

CONCLUSIONS

Discarding any allergy to β-lactams is as important as registering the allergy on medical records after testing the patient. A remarkable quantity of non-allergic patients is still addressed as actual allergic, in spite not being such. Labelling patients as β-lactams allergic may have consequences, short-term and long-term, for the patient but also for the health service budget.

Accuracy of Antibiotic Allergy Documentation and the Validity of Physicians' Decision in a Pediatric Tertiary Care Setting

Background

Patients allergic to antibiotics are at higher risk of receiving treatment with a broader spectrum, more harmful, and expensive agents. The aims of this study were (1) to assess the quality of documentation of antibiotics allergies in the electronic medical records (EMR) in a Pediatric tertiary care setting, and (2) to determine the validity of physicians’ decision to hold antibiotics prescriptions.

Methods

This is a retrospective cohort study at King Abdullah Specialized Children Hospital, Riyadh, Saudi Arabia. A review of the EMR and all Adverse Drug Reaction (ADR) reports of pediatric patients 1–14 years old, with a documented allergy to antibiotics from June 2016 until June 2019. The quality of documentation of antibiotics allergy was assessed based on the presence of four parameters: 1) allergy alert notification, 2) allergy severity classification, 3) setting notes, and 4) symptoms’ description. In addition, all physicians’ reports of allergy to antibiotics were cross-classified according to their corresponding ADR reports, and the validity of physicians’ documentation of allergy was assessed.

Results

Of a total of 105 Pediatric patients’ EMR, documentation of antibiotics allergy was available in 98 (93.3%), with the presence of symptoms description (83%), allergy notes (87%), severity (67%), and signs of alert (50.8%). Overall documentation quality was good for only 23.5% of patients, while it was poor for 35.7%. Physicians’ documentation of antibiotics allergy was 0.82 sensitive [with 0.18 risk of allergy] and 0.60 specific [with 0.40 unnecessary restrictions of prescriptions]. Of all children with possible/actual allergies, only 38.9% were referred to the immunology clinic.

Conclusion

The quality of documentation of antibiotic allergy in children and the validity of physicians’ decisions are less than satisfactory. Therefore, improving communications between all healthcare providers regarding patients’ allergy status and follow-up for further assessment of the reaction is recommended to improve patient care.

Risk Factors Associated With Nephrotoxicity During Outpatient Intravenous Vancomycin Administration

Background: Many studies have described an association between intravenous vancomycin and nephrotoxicity; however, the majority have evaluated incidence and risk factors among hospitalized patients. Outpatient administration of intravenous antibiotics is a growing practice and presents its own set of unique challenges. Objective: The aim of this study was to identify risk factors for vancomycin-associated nephrotoxicity in the outpatient setting. Methods: A case-control study of patients who received intravenous vancomycin through an Outpatient Parenteral Antimicrobial Therapy (OPAT) program was conducted. Patients were identified who developed an acute kidney injury (AKI) during treatment. The primary outcome was the incidence of AKI during treatment. Results: A total of 37 out of 130 patients (28.5%) met the criteria for AKI. AKI was more likely to occur in patients with a longer duration of therapy, higher maximum trough concentration, co-administration of a fluoroquinolone or metronidazole, and those who received another potentially nephrotoxic medication. Co-administration of a fluoroquinolone (OR = 5.96, P = 0.009, [CI: 1.59, 24.38]), any nephrotoxic medication (OR = 11.17, P < 0.001, [CI 3.14, 51.23]), and a higher maximum vancomycin trough (OR = 1.29, P < 0.001, [CI 1.17, 1.44]) were all indicative of a higher odds of an AKI. Conclusion: In this cohort, vancomycin-associated nephrotoxicity was common during outpatient intravenous antibiotic therapy. Co-administration of a fluoroquinolone, any nephrotoxic medication, and a higher maximum vancomycin trough were associated with AKI development. Further study is needed to determine how this impacts long-term clinical outcomes and what measures can be taken to reduce nephrotoxicity risk.

Effectiveness of interventions that support penicillin allergy assessment and de-labelling of patients by non-allergy specialists: a systematic review protocol

OBJECTIVE

This review will systematically examine and synthesize the evidence evaluating the effectiveness and safety of interventions that enable non-allergy specialist health care workers to assess allergy risk in patients with reported penicillin allergies and subsequently remove erroneous allergy records.

INTRODUCTION

The potential benefits of removing erroneous penicillin allergy labels (de-labeling) are wide-ranging. Penicillin allergy assessment and de-labeling is an antibiotic stewardship priority. Delivery of such assessment and de-labeling by non-allergy specialists has been reported in several studies, but the effectiveness and safety have not been formally synthesized. This is a necessary step in the upscaling of penicillin allergy assessment services.

INCLUSION CRITERIA

This review will consider quantitative studies using appropriate designs. The studies will include adults and pediatric patients who have undergone penicillin allergy assessment and de-labeling by non-allergy specialists in any health care setting.

METHODS

A range of databases will be searched to identify studies published in English, with no date limit. Unpublished studies and gray literature will also be searched. Title and abstract screening, and assessment of selected full texts against the inclusion criteria will be conducted by at least two independent reviewers. Identified studies will be assessed for methodological quality using standardized critical appraisal instruments. Data will be extracted and categorized using the EPOC taxonomy, and the effectiveness and safety of the intervention will be determined. Where possible, data will be pooled to facilitate meta-analysis. Data from heterogeneous studies will be reported narratively. The GRADE approach for grading the certainty of evidence will be followed.

SYSTEMATIC REVIEW REGISTRATION NUMBER

PROSPERO CRD42020219044.

De-labelling penicillin allergy in acutely hospitalized patients: a pilot study

Background

Penicillin allergy prevalence is internationally reported to be around 10%. However, the majority of patients who report a penicillin allergy do not have a clinically significant hypersensitivity. Few patients undergo evaluation, which leads to overuse of broad-spectrum antibiotics. The objective of this study was to monitor prevalence and implement screening and testing of hospitalized patients.

Methods

All patients admitted to the medical department in a local hospital in Oslo, Norway, with a self-reported penicillin allergy were screened using an interview algorithm to categorize the reported allergy as high-risk or low-risk. Patients with a history of low-risk allergy underwent a direct graded oral amoxicillin challenge to verify absence of a true IgE-type allergy.

Results

257 of 5529 inpatients (4.6%) reported a penicillin allergy. 191 (74%) of these patients underwent screening, of which 86 (45%) had an allergy categorized as low-risk. 54 (63%) of the low-risk patients consented to an oral test. 98% of these did not have an immediate reaction to the amoxicillin challenge, and their penicillin allergy label could thus be removed. 42% of the patients under treatment with antibiotics during inclusion could switch to treatment with penicillins immediately after testing, in line with the national recommendations for antibiotic use.

Conclusions

The prevalence of self-reported penicillin allergy was lower in this Norwegian population, than reported in other studies. Screening and testing of hospitalized patients with self-reported penicillin allergy is a feasible and easy measure to de-label a large proportion of patients, resulting in immediate clinical and environmental benefit. Our findings suggest that non-allergist physicians can safely undertake clinically impactful allergy evaluations.

β-lactam exposure outcome among patients with a documented allergy to penicillins post-implementation of a new electronic medical record system and alerting rules

BACKGROUND

Recent studies suggest that type I hypersensitivity cross-reactivity between β-lactam antibiotics is due to side chain similarity and not the common β-lactam ring. As a result, the prescriber-alerting rules of an electronic medical record (EMR) system were adjusted to only flag prescribers when prescribing penicillins or β-lactams with similar side chains (viz, cephalexin, cefadroxil, and cefoxitin) to patients with a documented allergy to penicillins. This study was conducted to assess and confirm the safety of the adjusted alerting rules; the primary outcome was the prevalence of anaphylaxis on β-lactam re-exposure.

METHODS

Retrospective chart review was conducted for patients who, under the reformed alerting rules, received a β-lactam antibiotic post-documentation of an allergy to penicillins in their EMR from April 2018 to July 2019 at a 268-bed community hospital. Given the volume of eligible patients, a 25% sample was randomly selected for review from initiation of the β-lactam antibiotic up to 30 days post-exposure to determine the prevalence of anaphylaxis.

RESULTS

Of the 325 charts reviewed, 300 patients (92.3%) received a β-lactam antibiotic with a different side chain than penicillins (not alerted on prescribing). Chart review of these 300 patients confirmed no reports of anaphylaxis secondary to β-lactam exposure (0%), and two patients developed non-anaphylactic delayed reactions (rash).

CONCLUSIONS

There were no reports of immediate life-threatening anaphylaxis under the reformed alerting rules, despite 25 patients (7.7%) receiving an alerted drug, such as piperacillin-tazobactam. The reformed alerting rules better reflect current literature and reduce the risk of prescriber-alerting fatigue without compromising patient safety. The occurrence of delayed reactions reinforced the need to monitor for these reactions on β-lactam antibiotic prescribing.

Penicillin Allergy Testing Is Cost-Saving: An Economic Evaluation Study

BACKGROUND

Having a penicillin allergy label is associated with the use of less appropriate and more expensive antibiotics and increased healthcare utilization. Penicillin allergy testing results in delabeling most allergy claimants and may be cost-saving. This study aimed to project whether penicillin allergy testing in patients reporting a penicillin allergy is cost-saving.

METHODS

In this economic evaluation study, we built decision models to project the economic impact of 2 strategies for a patient with a penicillin allergy label: (1) perform diagnostic testing (drug challenges, with or without skin tests); and (2) do not perform diagnostic testing. The health service perspective was adopted, considering costs with penicillin allergy tests, and with hospital bed-days/outpatient visits, antibiotic use, and diagnostic testing. Twenty-four base case decision models were built, accounting for differences in the diagnostic workup, setting (inpatient vs outpatient) and geographic region. Uncertainty was explored via probabilistic sensitivity analyses.

RESULTS

Penicillin allergy testing was cost-saving in all decision models built. For models assessing the performance of both skin tests and drug challenges, allergy testing resulted in average savings (in United States [US] dollars) of $657 for inpatients (US: $1444; Europe: $489) and $2746 for outpatients (US: $256; Europe: $6045). 75% of simulations obtained through probabilistic sensitivity analysis identified testing as the less costly option.

CONCLUSIONS

Penicillin allergy testing was projected to be cost-saving across different scenarios. These results are devised to inform guidelines, supporting the adoption of policies promoting widespread testing of patients with a penicillin allergy label.

Prevalence of Antibiotic Allergy Labels in a Tertiary Referral Center in Belgium

BACKGROUND

Antibiotic (AB) allergies are among the most frequently occurring adverse drug reactions. In US literature, AB allergy labels (AAL) are reported in 10% to 15% of patients' charts; however, large-scale European analyses are scarce.

OBJECTIVES

To retrospectively assess the prevalence of AAL in a tertiary referral hospital in Belgium between 2010 and 2018.

METHODS

Patients who consulted and/or were hospitalized during the study period, who had been labeled with an AB allergy, were selected for further analysis.

RESULTS

Of 1,009,598 unique patients (outpatients, n = 736,469; inpatients, n = 273,129), 28,147 patients (3%) were registered with 1 or more AAL, being 1% of outpatients (n = 9562) and 7% of inpatients (n = 18,585). Women were more likely to carry an AAL (68%) compared with men (32%, P < .001). In patients with an AAL, 9% had multiple labels and 5% had labels for multiple AB classes. Most frequently, beta-lactams were involved (84% of AAL), followed by quinolones (7%) and sulfonamides and macrolides (both 3%). Moreover, 88% of the reactions were self-reported, mostly being an unspecified rash (53%), whereas only 3% were considered confirmed AAL.

CONCLUSION

With an overall prevalence of 3%, the burden of AAL is less in our Western European center compared with US reports. However, this prevalence most likely still represents an overestimation of genuine AB allergic patients because most labels lack confirmation and/or specifications. Our work indicates that knowledge of the local epidemiology of AAL is necessary to estimate the impact of better allergy labeling and delabeling strategies.

Documentation of adverse drug reactions to opioids in an electronic health record

BACKGROUND

Allergy to opioids is the second most common drug allergy label in electronic health records (EHR). Adverse drug reactions (ADR) to opioids cause significant morbidity and contribute to healthcare costs, while incorrect opioid allergy labels may unnecessarily complicate patient management.

AIMS

To examine the documentation of opioid ADR in a large-scale hospital-based EHR.

METHODS

A cross-sectional retrospective review of EHR documentation of opioid ADR at four public hospitals in South Australia was conducted. Data were extracted from all ADR entries including the reported allergen, ADR category (allergy or intolerance) and reaction details. Expert criteria were used to determine consistency of ADR categorisation as allergy or intolerance.

RESULTS

Of 86 727 unique ADR reports, there were 13 781 ADR to opioids with most being entered as allergy (n = 8913, 64.7%) rather than intolerance (n = 4868, 35.3%). The most commonly documented reactions were nausea/vomiting (n = 3912, 28%), rash (n = 647, 5%), itch (n = 642, 5%) and hallucinations (n = 527, 4%). There were 362 (3%) ADR labels of anaphylaxis. Of those ADR containing a reaction description (n = 11 868), 89% of reports entered as allergy had a reaction description that was consistent with intolerance and 8% of the entered intolerances had descriptions consistent with allergy when assessed using predefined criteria.

CONCLUSIONS

This large EHR-based study demonstrates the high rate of opioid ADR labels in EHR. The majority of these labels were for symptoms suggestive of pharmacological intolerance. Reactions consistent with true allergy were uncommon. Systematic review of ADR by a dedicated clinical service would improve the accuracy of documentation.

Penicillin Allergy De-labeling Results in Significant Changes in Outpatient Antibiotic Prescribing Patterns

Unverified penicillin allergies are common but most patients with a penicillin allergy label can safely use penicillin antibiotics. Penicillin allergy labels are associated with poor clinical outcomes and overuse of second-line antibiotics. There is increasing focus on penicillin allergy "de-labeling" as a tool to improve antibiotic prescribing and antimicrobial stewardship. The effect of outpatient penicillin allergy de-labeling on long-term antibiotic use is uncertain. We performed a retrospective pre- and post- study of antibiotic dispensing patterns, from an electronic dispensing data repository, in patients undergoing penicillin allergy assessment at Auckland City Hospital, New Zealand. Over a mean follow-up of 4.55 years, 215/304 (70.7%) of de-labeled patients were dispensed a penicillin antibiotic. Rates of penicillin antibiotic dispensing were 0.24 (0.18-0.30) penicillin courses per year before de-labeling and 0.80 (0.67-0.93) following de-labeling with a reduction in total antibiotic use from 2.30 (2.06-2.54) to 1.79 (1.59-1.99) antibiotic courses per year. In de-labeled patients, the proportion of antibiotic courses that were penicillin antibiotics increased from 12.81 to 39.62%. Rates of macrolide, cephalosporin, trimethoprim/co-trimoxazole, fluoroquinolone, "other" non-penicillin antibiotic use, and broad-spectrum antibiotic use were all lower following de-labeling. Further, antibiotic costs were lower following de-labeling. In this study, penicillin allergy de-labeling was associated with significant changes in antibiotic dispensing patterns.

Analysis of the Costs Associated With the Elective Evaluation of Patients Labelled as Allergic to Beta-Lactams or Nonsteroidal Antiinflamatory Agents

Introduction: Being labelled as allergic to different drugs results in patients receiving other treatments, which are more toxic, less effective and more expensive. We aimed to analyze different studies of the costs of drug hypersensitivity assessment.

Methods: A bibliographic search on studies regarding this issue was performed, including the available scientific evidence up to June 2020. We searched three databases with terms related to costs and allergy testing in drug hypersensitivity reactions.

Results: Our search revealed 1,430 publications, of which 20 met the inclusion criteria. In the manuscript, prospective studies evaluating the costs of the evaluation of patients with suspected allergy to beta-lactams or non-steroidal anti-inflammatory drugs are analyzed. Also, comment is made on the costs associated with incorrect labeling as non-steroidal anti-inflammatory drug or penicillin hypersensitivity.

Conclusions: Taking all costs into account, the study of drug hypersensitivity is not expensive, particularly considering the economic and clinical consequences of labeling a patient with hypersensitivity to drugs.

Developing a behavioural intervention package to identify and amend incorrect penicillin allergy records in UK general practice and subsequently change antibiotic use

OBJECTIVES

To develop a behavioural intervention package to support clinicians and patients to amend incorrect penicillin allergy records in general practice. The intervention aimed to: (1) support clinicians to refer patients for penicillin allergy testing (PAT), (2) support patients to attend for PAT and (3) support clinicians and patients to prescribe or consume penicillin, when indicated, following a negative PAT result.

METHODS

Theory-based, evidence-based and person-based approaches were used in the intervention development. We used evidence from a rapid review, two qualitative studies, and expert consultations with the clinical research team to identify the intervention 'guiding principles' and develop an intervention plan. Barriers and facilitators to the target behaviours were mapped to behaviour change theory in order to describe the proposed mechanisms of change. In the final stage, think-aloud interviews were conducted to optimise intervention materials.

RESULTS

The collated evidence showed that the key barriers to referral of patients by clinicians were limited experience of referral and limited knowledge of referral criteria and PAT. Barriers for patients attending PAT were lack of knowledge of the benefits of testing and lack of motivation to get tested. The key barriers to the prescription and consumption of first-line penicillin following a negative test result were patient and clinician beliefs about the accuracy of PAT and whether taking penicillin was safe. Intervention materials were designed and developed to address these barriers.

CONCLUSIONS

We present a novel behavioural intervention package designed to address the multiple barriers to uptake of PAT in general practice by clinicians and patients. The intervention development details how behaviour change techniques have been incorporated to hypothesise how the intervention is likely to work to help amend incorrect penicillin allergy records. The intervention will go on to be tested in a feasibility trial and randomised controlled trial in England.

'Warning: allergic to penicillin': association between penicillin allergy status in 2.3 million NHS general practice electronic health records, antibiotic prescribing and health outcomes

BACKGROUND

The prevalence of reported penicillin allergy (PenA) and the impact these records have on health outcomes in the UK general population are unknown. Without such data, justifying and planning enhanced allergy services is challenging.

OBJECTIVES

To determine: (i) prevalence of PenA records; (ii) patient characteristics associated with PenA records; and (iii) impact of PenA records on antibiotic prescribing/health outcomes in primary care.

METHODS

We carried out cross-sectional/retrospective cohort studies using patient-level data from electronic health records. Cohort study: exact matching across confounders identified as affecting PenA records. Setting: English NHS general practices between 1 April 2013 and 31 March 2014. Participants: 2.3 million adult patients. Outcome measures: prevalence of PenA, antibiotic prescribing, mortality, MRSA infection/colonization and Clostridioides difficile infection.

RESULTS

PenA prevalence was 5.9% (IQR = 3.8%-8.2%). PenA records were more common in older people, females and those with a comorbidity, and were affected by GP practice. Antibiotic prescribing varied significantly: penicillins were prescribed less frequently in those with a PenA record [relative risk (RR)  = 0.15], and macrolides (RR = 4.03), tetracyclines (RR = 1.91) nitrofurantoin (RR = 1.09), trimethoprim (RR = 1.04), cephalosporins (RR = 2.05), quinolones (RR = 2.10), clindamycin (RR = 5.47) and total number of prescriptions were increased in patients with a PenA record. Risk of re-prescription of a new antibiotic class within 28 days (RR = 1.32), MRSA infection/colonization (RR = 1.90) and death during the year subsequent to 1 April 2013 (RR = 1.08) increased in those with PenA records.

CONCLUSIONS

PenA records are common in the general population and associated with increased/altered antibiotic prescribing and worse health outcomes. We estimate that incorrect PenA records affect 2.7 million people in England. Establishing true PenA status (e.g. oral challenge testing) would allow more people to be prescribed first-line antibiotics, potentially improving health outcomes.

A Prospective Study of Costs Associated with the Evaluation of β-Lactam Allergy in Children

OBJECTIVE

To evaluate the costs associated with evaluation of β-lactam allergy in children labeled as allergic.

STUDY DESIGN

We performed a prospective year-long real life observational study designed to evaluate all pediatric patients with suspected β-lactam allergy who consulted for allergy evaluation. Direct and indirect costs were systematically recorded. Direct healthcare costs were calculated by taking into account the number of visits and all complementary and diagnostic tests performed. Direct nonhealthcare costs were calculated by considering the number of visits and the kilometers from their homes to the clinic. Finally, indirect costs were evaluated by considering the absenteeism of parents or other companions who took the children to the clinic.

RESULTS

A total of 40 children with suspected allergy to β-lactams were evaluated in our outpatient clinic from June 1, 2017 to May 31, 2018. Total direct healthcare costs were $5038.03, with an average cost per patient of $125.95. Direct nonhealthcare costs reached $901.87 ($22.55 per patient) and indirect nonhealthcare costs reached $6384.35 ($159.61 per patient). The total cost was $12 324.25, a cost of $308.11 per patient.

CONCLUSIONS

Elective evaluation of β-lactam allergy and delabeling children who are not allergic is not expensive. In addition, it could save future expenses because of an unnecessary lifelong use of alternative antibiotics that are usually more expensive, less effective, and more frequently associated with antimicrobial resistance and different side effects.

Implementation of a pharmacist-led penicillin allergy de-labelling service in a public hospital

BACKGROUND

Inaccurate allergy labelling results in inappropriate antimicrobial management of the patient, which may affect clinical outcome, increase the risk of adverse events and increase costs. Inappropriate use of alternative antibiotics has implications for antimicrobial stewardship programmes and microbial resistance.

METHODS

All adult inpatients labelled as penicillin allergic were identified and screened for eligibility by the study pharmacist. An accurate allergy and medication history was taken. Patients were 'de-labelled', underwent oral challenge or were referred to an immunology clinic, if study criteria were met. All patients included in the study were followed-up 1 year after intervention.

RESULTS

Two hundred and fifty eligible patients with a label of 'penicillin allergy' were identified. The prevalence of reported penicillin allergy at Middlemore Hospital was 11%. We found that 80% of study patients could be 'de-labelled'. Of those, 80% were 'de-labelled' after an interview with the pharmacist alone, 16% had an uneventful oral challenge and 4% were deemed to be inappropriately labelled after referral to an immunology clinic. Appropriately labelled patients accounted for 20% of the study population. Changes to inpatient antibiotic therapy were recommended in 61% of 'de-labelled' patients, of which no patients had adverse events after commencing on penicillin antibiotics. At the 1 year follow-up, 98% of patients who were 'de-labelled' had no adverse events to repeated administration of penicillin antibiotics.

CONCLUSIONS

This study showed that a pharmacist-led allergy management service is a safe option to promote antimicrobial stewardship and appropriate allergy labelling.

GRAded oral challenge for Drug allergy Evaluation-Delabelling described through families' voices

BACKGROUND

Children are often diagnosed with an antibiotic allergy, with little investigation to confirm whether it is a true allergy. Recent studies support the use of oral challenges to confirm antibiotic allergy. Yet, little is known about families' perceptions of these challenges, or experiences of living with a misdiagnosis, often for many years.

OBJECTIVE

To describe how families with a child previously labelled as "antibiotic allergic," but who has subsequently been delabelled, perceive the experience of misdiagnosis and subsequent delabelling.

METHODS

We performed semi-structured interviews with parents whose children had recently completed a graded oral challenge for antibiotic allergy. Interview transcripts were analysed concurrently, but independently, by two investigators, using content analysis.

RESULTS

A total of 15 parents (14 individual interviews; 1 mother-father dyad) participated. Children were, on average, 5.04 ± 4.5 years and were first diagnosed in infancy (mean age: 1.82 ± 1.48 years) subsequent to a rash (14/14; 100%), and commonly at a walk-in clinic (6/14; 42.9%). We identified four themes: (1) A red, raised rash results in a quick diagnosis despite a lack of testing, (2) sensitive care allays concerns, (3) delabelling brings relief, but also mystery and calls for proper diagnoses, and (4) quick diagnoses are reckless, but manageable through downward comparisons.

CONCLUSION AND CLINICAL RELEVANCE

These findings underscore the importance of a careful physical examination and clinical history of the patient, but also an ongoing dialogue to support families, both of which would ideally begin at the time of initial investigation.

Inappropriate Antibiotic Allergy Documentation in Health Records: A Qualitative Study on Family Physicians' and Pharmacists' Experiences

PURPOSE

It is hypothesized that 90% of antibiotic allergies documented in patients' health records are not actual, potentially life threatening, type I allergies mediated by IgE. This distinction is important because such documentation increases antibiotic resistance, as more second-choice and broad-spectrum antibiotics are then used. Evidence is lacking regarding causes of this inappropriate documentation. To develop interventions aimed at improving documentation, we explored experiences of family physicians and pharmacists in this area.

METHODS

We conducted a qualitative study among family physicians and pharmacists using focus group discussions, based on purposeful sampling and a naturalistic approach. Discussions were audio-recorded, transcribed verbatim, and analyzed in duplicate by means of constant comparative technique.

RESULTS

We conducted 4 focus group discussions among 34 family physicians and 10 pharmacists, from which 3 main themes emerged: (1) magnitude and awareness of the problem of inappropriate antibiotic allergy documentation, (2) origin of the problem, and (3) approaches for addressing the problem. Participants noted that the magnitude of contamination of medical files with inappropriate documentation leads to skepticism about current documentation. Major hindering factors are electronic health record systems and electronic communication. In addition, family physicians and pharmacists believed they had insufficient knowledge about antibiotic allergies and called for tools to rectify inappropriate allergy documentation and facilitate proper documentation going forward.

CONCLUSIONS

Family physicians and pharmacists perceive that few documented antibiotic allergies are in fact correct. Electronic health record barriers and communication barriers, as well as a lack of knowledge and facilitating tools, are main causes for numerous inappropriately documented antibiotic allergies and therefore targets for improving documentation in the future.

Accuracy of penicillin allergy diagnostic tests: A systematic review and meta-analysis

BACKGROUND

Having a penicillin allergy label associates with a higher risk for antibiotic resistance and increased health care use.

OBJECTIVE

We sought to assess the accuracy of skin tests and specific IgE quantification in the diagnostic evaluation of patients reporting a penicillin/β-lactam allergy.

METHODS

We performed a systematic review and diagnostic accuracy meta-analysis, searching on MEDLINE, Scopus, and Web of Science. We included studies conducted in patients reporting a penicillin allergy and in whom skin tests and/or specific IgE quantification were performed and compared with drug challenge results. We quantitatively assessed the accuracy of diagnostic tests with bivariate random-effects meta-analyses. Meta-regression and subgroup analyses were performed to explore causes of heterogeneity. Studies' quality was evaluated using QUADAS-2 criteria.

RESULTS

We included 105 primary studies, assessing 31,761 participants. Twenty-seven studies were assessed by bivariate meta-analysis. Skin tests had a summary sensitivity of 30.7% (95% CI, 18.9%-45.9%) and a specificity of 96.8% (95% CI, 94.2%-98.3%), with a partial area under the summary receiver-operating characteristic curve of 0.686 (I² = 38.2%). Similar results were observed for subanalyses restricted to patients reporting nonimmediate maculopapular exanthema or urticaria/angioedema. Specific IgE had a summary sensitivity of 19.3% (95% CI, 12.0%-29.4%) and a specificity of 97.4% (95% CI, 95.2%-98.6%), with a partial area under the summary receiver-operating characteristic curve of 0.420 (I² = 8.5%). Projected predictive values mainly reflect the low frequency of true penicillin allergy.

CONCLUSIONS

Skin tests and specific IgE quantification appear to have low sensitivity and high specificity. Because current evidence is insufficient for assessing the role of these tests in stratifying patients for delabeling, we identified key requirements needed for future studies.

A Closer Look at Penicillin Allergy History: Systematic Review and Meta-Analysis of Tolerance to Drug Challenge

BACKGROUND

True allergy to penicillin is rare, despite the high frequency with which it is reported. While most patients reporting penicillin allergy are not prone to anaphylaxis, it is not currently known what percentage of these patients will tolerate dose challenges of penicillin-based antibiotics. This review aims to determine the rate of tolerance in patients reporting penicillin allergy when challenged with penicillin-based antibiotics.

METHODS

We searched MedLine, Embase, and Cochrane Library for publications with English language translations between the years 2000 and 2017. We included randomized controlled trials, quasi-experimental, and observational studies of participants reporting penicillin allergy who received at least one systemic dose of a penicillin in the form of a drug challenge. At least 2 independent reviewers extracted data from included studies and assessed the quality of each included study. To generate primary outcome data, we calculated a summary estimate rate of penicillin tolerance from a pooled proportion of participants receiving penicillin with no adverse effects.

RESULTS

Initial literature search yielded 2945 studies, of which 23 studies were ultimately included in our review; 5056 study participants with reported history of penicillin allergy were challenged with a penicillin. After weighting for study sample size, a pooled average of 94.4% (95% confidence interval, 93.7%-95%) of participants tolerated the dose challenge without any adverse reaction.

CONCLUSION

Misrepresented penicillin allergy drives unnecessary use of alternative antibiotics, which may be less effective, more toxic, and more expensive than using penicillin. In addressing the problem of penicillin allergy over-diagnosis, evaluation should go beyond risk for type 1 hypersensitivity. Our data suggest that 94.4% of 5056 participants with reported penicillin allergy determined to be clinically appropriate for allergy evaluation tolerated repeat administration of penicillin-based antibiotics without any adverse reactions. This review generates meaningful information useful to clinical predictive analytics, in evaluating and managing patients with a reported history of penicillin allergy.

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.

An educational intervention about the classification of penicillin allergies: effect on the appropriate choice of antibiotic therapy in pregnant women

BACKGROUND

Most pregnant women who self-report penicillin allergy are not truly penicillin-allergic and this misunderstanding often leads to administration of inappropriate antibiotic therapy. Decision algorithms have been developed to guide antibiotic selection but major discrepancies have been reported between guidelines and clinical practice. We aimed to optimize the prescription of antibiotics for pregnant women who self-reported penicillin allergy, using an educational intervention about the classification of penicillin allergies that targeted gynecologists, anesthesiologists and midwives.

METHODS

This quasi-experimental study assessed the effect of an educational intervention about the classification of penicillin allergy. For six months, a combination of two strategies was used, namely dissemination of printed educational materials and group education. The principal study endpoint was the appropriateness of the antibiotic therapy, defined in advance for each level of allergic risk.

RESULTS

The pre-intervention phase included 903 women; one year after its conclusion, the post-intervention phase began and included 892 women. The prevalence of self-reported penicillin allergy was stable over the two periods (6.8% before vs 5.4% after, P=0.24). The clinical classification of penicillin allergies was more often used after the educational intervention (68% vs 100%, P<0.001). The appropriateness of the antibiotic therapy prescribed to self-reported penicillin allergic-women increased significantly between the two periods, from 5/29 (17.2%) to 18/27 (66.7%, P<0.001).

CONCLUSION

An educational intervention about penicillin allergy classification was associated with an improvement in the choice of appropriate antibiotic therapy among women who had reported penicillin allergy.

Adherence to antibiotic guidelines and reported penicillin allergy: pooled cohort data on prescribing and allergy documentation from two English National Health Service (NHS) trusts

OBJECTIVE

To investigate documentation of antimicrobial allergy and to determine prescribing adherence to local antibiotic guidelines for inpatients with and without reported penicillin allergy treated for infection in a National Health Service (NHS) context.

SETTING

Data were collected at two English hospital NHS trusts over two time-periods: June 2016 and February 2017.

DESIGN

Cohort study. Trust 1 data were sourced from prospective point prevalence surveys. Trust 2 data were extracted retrospectively from an electronic report.

PARTICIPANTS

Inpatients treated for urinary tract infection (UTI), community-acquired pneumonia (CAP), hospital-acquired pneumonia (HAP) and skin and soft tissue infection (SSTI). Data on allergy were collected, and antibiotic selection assessed for adherence to trust guidelines with differences between groups presented as adjusted ORs.

RESULTS

A total of 1497 patients were included, with 2645 antibiotics orders. Patients were treated for CAP (n=495; 33.1%), UTI (407; 27.2%), HAP (330; 22%) and SSTI (265; 17.7%). There were 240 (16%) patients with penicillin allergy. Penicillin allergy was recorded as allergy (n=52; 21.7%), side effect (27; 11.3%) and no documentation (161; 67.1%). Overall, 2184 (82.6%) antibiotic orders were guideline-adherent. Adherence was greatest for those labelled penicillin allergy (453 of 517; 87.6%) versus no allergy (1731 of 2128; 81.3%) (OR 0.52 (95% CI 0.37 to 0.73) p<0.001). Guideline-adherence for CAP was higher if penicillin allergy (151 of 163; 92.6%) versus no allergy (582 of 810; 71.9%) (OR 0.20 (95% CI 0.10 to 0.37) p<0.001). There was no difference in adherence between those with and without penicillin allergy for UTI, HAP or SSTI treatment.

CONCLUSIONS

A relatively high proportion of patients had a penicillin allergy and two thirds of these had no description of their allergy, which has important implications for patient safety. Patients with penicillin allergy treated for CAP, received more guideline adherent antibiotics than those without allergy. Future studies investigating the clinical impact of penicillin allergy should include data on adherence to antibiotic guidelines.

Presumed β-Lactam Allergy and Cross-reactivity in the Operating Theater: A Practical Approach

A β-lactam allergy is the most common suspected in-hospital drug allergy. This article aims to provide a practical approach to a patient with presumed β-lactam allergy in the perioperative setting.

Supplemental Digital Content is available in the text.

Patient-reported allergies predict postoperative outcomes and psychosomatic markers after spine surgery

BACKGROUND CONTEXT

Prior studies have shown that patient-reported allergies can be prognostic of poorer postoperative outcomes.

PURPOSE

The objective of this study was to investigate the correlation between self-reported allergies and outcomes after cervical or lumbar spine surgery.

STUDY DESIGN/SETTING

This is a retrospective cohort study at a single tertiary care institution.

PATIENT SAMPLE

The patient sample included all patients undergoing cervical or lumbar spine surgery from 2009 to 2014.

OUTCOME MEASURES

The primary outcome measure was change in the EuroQol-5 Dimensions (EQ-5D) after surgery. Secondary outcomes included changes in the Pain Disability Questionnaire (PDQ) and in the Patient Health Questionnaire-9 (PHQ-9), achievement of the minimal clinically important difference (MCID) in these measures, and cost of admission.

METHODS

Before and after surgery, EQ-5D, PDQ, and PHQ-9 were recorded for patients with available data. Paired Student t tests were used to compare changes in these measures after surgery. Multivariable linear and logistic regressions were used to assess the relationship between the log transformation of the total number of allergies and outcomes.

RESULTS

A total of 592 cervical patients and 4,465 lumbar patients were included. The median number of reported allergies was two. The EQ-5D index increased from 0.539 to 0.703 for cervical patients and from 0.530 to 0.676 for lumbar patients (p<.01 for both). Patients experienced significant pain improvement by the PDQ (80.1-58.2 for cervical patients and 79.4-58.1 for lumbar patients, p<.01). Using multivariable logistic regression, the log transformation of the number of allergies predicted significantly higher odds of achieving the PDQ MCID (odds ratio [OR]=2.09, 95% confidence interval [CI] 1.05-4.15, p=.02, for cervical patients; OR=1.30, 95% CI 1.03-1.68, p=.03, for lumbar patients). However, this relationship was not durable for patients with follow-up exceeding 1 year. The log transformation of the number of allergies for lumbar patients predicted a significantly increased cost of admission (β=$3,597, p<.01) and trended toward significance among cervical patients (β=$1,842, p=.10).

CONCLUSIONS

Patient-reported allergies correlate with subjective improvement in pain and disability after spine surgery and may serve as a marker of postoperative outcomes. The relationship between allergies and PDQ improvement may be secondary to the short-term expectation-actuality discrepancy, as this relationship was not durable beyond 1 year.

Penicillin allergy de-labelling ahead of elective surgery: feasibility and barriers

BACKGROUND

Around 10-15% of the in-patient population carry unsubstantiated 'penicillin allergy' labels, the majority incorrect when tested. These labels are associated with harm from use of broad-spectrum non-penicillin antibiotics. Current testing guidelines incorporate both skin and challenge tests; this is prohibitively expensive and time-consuming to deliver on a large scale. We aimed to establish the feasibility of a rapid access de-labelling pathway for surgical patients, using direct oral challenge.

METHODS

'Penicillin allergic' patients, recruited from a surgical pre-assessment clinic, were risk-stratified using a screening questionnaire. Patients at low risk of true, immunoglobulin E (IgE)-mediated allergy were offered direct oral challenge using incremental amoxicillin to a total dose of 500 mg. A 3-day course was completed at home. De-labelled patients were followed up to determine antibiotic use in surgery, and attitudes towards de-labelling were explored.

RESULTS

Of 219 patients screened, 74 were eligible for inclusion and offered testing. We subsequently tested 56 patients; 55 were de-labelled. None had a serious reaction to the supervised challenge, or thereafter. On follow-up, 17 of 19 patients received appropriate antimicrobial prophylaxis during surgery. Only three of 33 de-labelled patients would have been happy for the label to be removed without prior specialist testing.

CONCLUSION

Rapid access de-labelling, using direct oral challenge in appropriately risk-stratified patients, can be incorporated into the existing surgical care pathway. This provides immediate and potential long-term benefit for patients. Interest in testing is high among patients, and clinicians appear to follow clinic recommendations. Patients are unlikely to accept removal of their allergy label on the basis of history alone.

CLINICAL TRIAL REGISTRATION

ClinicalTrials.gov: AN17/92982.

Enhancing antibiotic stewardship by tackling "spurious" penicillin allergy

Approximately 90-99% of patients with a label of penicillin allergy (PenA) are not allergic when comprehensively investigated. An inaccurate label of PenA has major public health implications-longer hospital stay, more frequent hospital admissions, greater use of fluoroquinolones, glycopeptides, cephalosporins and other expensive antibiotics resulting in significantly higher costs to the health service and predisposing to Clostridium difficile, methicillin-resistant Staphylococcus aureus infections and vancomycin-resistant enterococcus. We describe lessons learnt from recent studies regarding possible reasons contributing to an inaccurate label of PenA as well as propose a concerted multidisciplinary approach to address this important public health problem. Given the unmet need for allergy services in the UK and several other countries and knowledge gaps regarding PenA amongst healthcare professionals, we describe the potential role for a computerized clinical decision support system to enable non-specialists rapidly identify and de-label "low-risk" hospitalized patients with a label of PenA thereby obviating the need for allergy tests. This approach however needs rigorous evaluation for feasibility, safety, patient and physician acceptability, cost-effectiveness and its compatibility with information technology systems currently employed in the health service.

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.

Higher risk of revision for infection using systemic clindamycin prophylaxis than with cloxacillin

Background and purpose - Clindamycin has not been compared with other antibiotics for prophylaxis in arthroplasty. Since 2009, the Swedish Knee Arthroplasty Register (SKAR) has been collecting information on the prophylactic antibiotic regime used at every individual operation. In Sweden, when there is allergy to penicillin, clindamycin has been the recommended alternative. We examined whether there were differences in the rate of revision due to infection depending on which antibiotic was used as systemic prophylaxis. Patients and methods - Patients who had a total knee arthroplasty (TKA) performed due to osteoarthritis (OA) during the years 2009-2015 were included in the study. Information on which antibiotic was used was available for 80,018 operations (55,530 patients). Survival statistics were used to calculate the rate of revision due to infection until the end of 2015, comparing the group of patients who received cloxacillin with those who received clindamycin as systemic prophylaxis. Results - Cloxacillin was used in 90% of the cases, clindamycin in 7%, and cephalosporins in 2%. The risk of being revised due to infection was higher when clindamycin was used than when cloxacillin was used (RR =1.5, 95% CI: 1.2-2.0; p = 0.001). There was no significant difference in the revision rate for other causes (p = 0.2). Interpretation - We advise that patients reporting allergic reaction to penicillin should have their allergic history explored. In the absence of a clear history of type-I allergic reaction (e.g. urticaria, anaphylaxis, or bronchospasm), we suggest the use of a third-generation cephalosporin instead of clindamycin as perioperative prophylaxis when undergoing a TKR. No recommendation can be given regarding patients with type-1 allergy.