Economic Burden of Patient-Reported Penicillin Allergy on Total Hip and Total Knee Arthroplasty

Labelling patients as allergic to beta-lactam antibiotics is associated with periprosthetic joint infection up to five years following knee arthroplasty

Aims

Periprosthetic joint infections (PJIs) represent a significant complication of total knee arthroplasty (TKAs). However, the influence of drug or beta-lactam (BL) antibiotic allergy labelling of patients on PJI remains largely unknown. In this study, we examine the association between patients labelled with a BL allergy and the occurrence of PJI among patients undergoing TKA. We also assess the prevalence of incorrect patient labelling and explore the feasibility of a multidisciplinary drug allergy testing initiative to detect mislabelling.

Methods

Longitudinal data from all patients who underwent TKA between January 1993 and December 2021 were analyzed. We investigated the association between different risk factors and PJI, with particular focus on patients labelled as having an antibiotic drug allergy. The outcomes of patients with and without a labelled BL allergy were compared. Additionally, patients labelled as having a BL allergy and who had undergone or were scheduled for TKA were prospectively investigated by formal allergy assessment.

Results

Out of 4,730 TKAs, the overall incidence of PJI was 1.0% (47/4,730). Patients labelled as having a BL allergy had a higher incidence of PJI within the first five years post-TKA compared to those without (3.0% (5/165) vs 0.7% (34/4,565); p = 0.001). The presence of a BL allergy label was identified as an independent risk factor for PJI (hazard ratio 4.86 (95% CI 2.05 to 11.53); p < 0.001). Following negative drug provocation testing, the majority of patients (95% (21/22)) evaluated with BL allergy labels were successfully delabelled.

Conclusion

In this longitudinal study, patients labelled as having a BL allergy were associated with having increased risk of PJI following TKA, particularly within the first five years. Given the high rate of patients being mislabelled, we recommend that patients labelled as having a BL allergy should be prioritized for formal allergy assessment and evaluation. Further studies on the impact of preoperative antibiotic allergy delabelling initiatives should be encouraged.

Direct oral penicillin challenge in secondary care with low-risk patients: the SPACE mixed-methods study with cost-effectiveness analysis

Background

One in five inpatients carries a penicillin allergy label. However, 90-95% of labels are incorrect. Penicillin allergy labels lead to increased risk for serious hospital infections and longer hospital stay and are associated with higher estimated healthcare costs. Penicillin allergy testing is onerous and requires a specialist. Routine inpatient testing is not available. Recent evidence suggests that a direct oral penicillin challenge delivered by non-allergy specialists is safe in 'low risk' patients, who are highly unlikely to be allergic based on history.

Aims

To explore behaviour, attitudes and acceptability of patients, healthcare professionals and managers regarding a direct oral penicillin challenge in 'low risk' patients. To inform development of an implementation framework and determine potential cost-effectiveness.

Methods

This study (1 May 2021-30 April 2023) involved delivery of direct oral penicillin challenge by non-allergy specialists across three clinical settings (medical/infectious diseases wards, presurgical and haematology-oncology units) at three hospitals. The study had three workstreams: Workstream 1: Screening for potential suitability. Patients were stratified into 'low risk' and 'high risk'. 'Low-risk' patients underwent direct oral penicillin challenge. Workstream 2: One-to-one semistructured interviews with patients (N = 43) and focus group (N = 28) discussions with stakeholders. Workstream 3: Care pathway mapping, decision-analytic modelling and value of information analysis were carried out to determine potential cost-effectiveness of direct oral penicillin challenge.

Results

One thousand and fifty-four of 2257 screened patients were eligible, 270 of 643 approached patients consented (42%). Two hundred and fifty-nine patients were risk-stratified (155 'low risk'; 104 'high risk'). Of the 155 'low risk' patients, 126 underwent direct oral penicillin challenge, 122 (97%) were de-labelled with no serious allergic reactions and 43 patients were interviewed. Low-risk patients accepted their allergy labels, had limited knowledge of the adverse impact and most were keen to have their labels reviewed. Healthcare professionals demonstrated a risk-averse approach, although would engage in the intervention with training, resource availability and a governance framework in place. The total costs of the direct oral penicillin challenge pathway were higher than the costs of direct oral penicillin challenge alone (£940 vs. £98-288 per patient). There were minimal expected savings in antibiotic and hospital costs in the short term and potentially large healthcare cost savings over 5 years.

Limitations

Relatively small sample size for direct oral penicillin challenge, poor conversion rate, particularly in acute settings, patients with limited English language proficiency could not be included and the study was not sufficiently powered and controlled to conduct a cost-effectiveness evaluation.

Conclusions

This first multicentre United Kingdom study showed that non-allergy specialist-led direct oral penicillin challenge is feasible in secondary care. A high proportion of direct oral penicillin challenges were successful, with positive feedback from patients. Majority of screened patients did not progress through the study pathway. Going forward, a multipronged approach is needed to enhance equitability of direct oral penicillin challenge in routine practice. Follow-up mechanisms to consider the intervention during a clinically stable state and a governance framework for those lacking capacity to consent are needed. The cost of delivering a direct oral penicillin challenge pathway in its entirety is significantly higher than the costs of performing direct oral penicillin challenge per se.

Future work

A randomised controlled trial with long-term follow-up is needed to determine the cost-effectiveness of direct oral penicillin challenge.

Study registration

This study is registered as ISRCTN55524365.

Funding

This award was funded by the National Institute for Health and Care Research (NIHR) Health and Social Care Delivery Research programme (NIHR award ref: NIHR129069) and is published in full in Health and Social Care Delivery Research; Vol. 13, No. 9. See the NIHR Funding and Awards website for further award information.

Pre-Operative Management of the Penicillin Allergic Patient: A Narrative Review

Penicillin is a frequently reported medication allergy. The beta-lactam ring shared between cephalosporins and penicillin often leads to the use of alternative antibiotics for surgical prophylaxis due to concern for cross-reactivity, despite a true IgE-mediated hypersensitivity being very rare. This misconception leads to the use of less effective second line antibiotics, such as clindamycin or vancomycin, for penicillin-allergic patients which has been shown to increase odds of postoperative infection in elective knee arthroplasty, shoulder arthroplasty and spine surgery. Preoperative penicillin allergy testing has been demonstrated to be a cost-effective measure in the prevention of prosthetic joint infection and is suggested for all penicillin-allergic patients in the peri-operative setting. This review highlights and summaries the outcomes of orthopaedic procedures in patients with reported penicillin allergies and discusses potential solutions to the perioperative challenges of patients with reported penicillin allergies.

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

Objectives

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

Methods

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

Results

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

Conclusions

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

Second-Line Antibiotic Agents in Patient-Reported Penicillin or Cephalosporin Allergy Have No Negative Impact on Antibiotic Resistance After Hip and Knee Arthroplasty

BACKGROUND

The aim of the present study was to compare causative bacteria and their antibiotic resistance profiles in patients developing a periprosthetic joint infection (PJI) based on preoperative prophylactic antibiotic regimens in primary total hip (THA) and primary total and unicompartmental knee arthroplasty (TKA/UKA).

METHODS

We reviewed all cases of PJI occurring after primary THA and primary TKA/UKA, between 2011 and 2020 in a tertiary referral hospital. The standard preoperative prophylactic antibiotic for primary joint arthroplasty was cefuroxime and recommended second-line agent was clindamycin. Patients were divided by the replaced joint and analyzed independently.

RESULTS

In the THA group, culture-positive PJI was detected in 61 of 3,123 (2.0%) cefuroxime-administered cases and 6 of 206 (2.9%) noncefuroxime-administered cases. In the TKA/UKA group, culture positive PJI was identified in 21 of 2,455 (0.9%) cefuroxime-administered cases and in 3 of 211 (1.4%) noncefuroxime administered cases. The most commonly isolated bacteria in both groups were coagulase negative staphylococci (CNS). There were no statistically significant differences of pathogen spectrum depending on the preoperative antibiotic regimen detected. Antibiotic resistance of isolated bacteria was significantly different in 4 of 27 (14.8%) analyzed antibiotics in THA and in 3 of 22 (13.6%) analyzed antibiotics in TKA/UKA. In all cohorts, a high occurrence of oxacillin-resistant CNS (50.0 to 100.0%) and clindamycin-resistant CNS (56.3 to 100.0%) has been observed.

CONCLUSION

The use of the second-line antibiotic did not influence the pathogen spectrum or antibiotic resistance. However, an alarmingly high proportion of CNS strains was resistant to clindamycin.

Prevalence of reported penicillin allergy and associations with perioperative complications, length of stay, and cost in patients undergoing elective cancer surgery

Objective

Up to 10% of patients report penicillin allergy (PA), although only 1% are truly affected by Ig-E-mediated allergies. PA has been associated with worse postoperative outcomes, but studies on the impact of reported PA in cancer patients are lacking, and especially in these multimorbid patients, a non-complicated course is of utmost importance.

Methods

Retrospective analysis of patients undergoing elective oncological surgery at a tertiary reference center. Data on surgical site infections (SSI), postoperative complications (measured by Clavien-Dindo classification and Comprehensive Complication Index (CCI)), hospitalization duration, and treatment costs were collected.

Results

Between 09/2019 and 03/2020, 152 patients were identified. 16/152 patients (11%) reported PA, while 136/152 (89%) did not. There were no differences in age, BMI, Charlson Comorbidity Index, and smoking status between groups (p > 0.4). Perioperative beta-lactam antibiotics were used in 122 (89.7%) and 15 (93.8%) patients without and with reported PA, respectively. SSI and mean numbers of infections occurred non-significantly more often in patients with PA (p = 0.2 and p = 0.47). The median CCI was significantly higher in PA group (26 vs. 51; p = 0.035). The median hospitalization duration and treatment costs were similar between non-PA and PA groups (4 vs 3 days, p = 0.8; 16'818 vs 17'444 CHF, p = 0.4).

Conclusions

In patients undergoing cancer surgery, reported PA is common. Failure to question the unproven PA may impair perioperative outcomes. For this reason, patient and provider education on which reactions constitute a true allergy would also assist in allergy de-labeling. In addition, skin testing and oral antibiotic challenges can be performed to identify the safe antibiotics and to de-label appropriate patients.

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

BACKGROUND

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

OBJECTIVE

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Differences in beta-lactam and penicillin allergy: Beyond the West and focusing on Asia-Pacific

Beta-lactam (BL) antibiotic "allergy" labels are common, but often overdiagnosed. Although much research has been focused on the BL allergy and the delabelling process in the West, studies from other parts of the world remain sparse. This review outlines the contrasting global epidemiology, shifting clinical practices and disparities of BL allergy in the Asia-Pacific region compared with the West. Innovative strategies to overcome barriers in BL allergy workup are discussed and potential directions for future research and service development are also proposed.

BSACI guideline for the set-up of penicillin allergy de-labelling services by non-allergists working in a hospital setting

The Standards of Care Committee of the British Society for Allergy and Clinical Immunology (BSACI) and a committee of experts and key stakeholders have developed this guideline for the evaluation and testing of patients with an unsubstantiated label of penicillin allergy. The guideline is intended for UK clinicians who are not trained in allergy or immunology, but who wish to develop a penicillin allergy de-labelling service for their patients. It is intended to supplement the BSACI 2015 guideline "Management of allergy to penicillin and other beta-lactams" and therefore does not detail the epidemiology or aetiology of penicillin allergy, as this is covered extensively in the 2015 guideline (1). The guideline is intended for use only in patients with a label of penicillin allergy and does not apply to other beta-lactam allergies. The recommendations include a checklist to identify patients at low risk of allergy and a framework for the conduct of drug provocation testing by non-allergists. There are separate sections for adults and paediatrics within the guideline, in recognition of the common differences in reported allergy history and likelihood of true allergy.

Are Patient-Reported Drug Allergies Associated With Prosthetic Joint Infections and Functional Outcomes Following Total Hip and Knee Arthroplasty?

BACKGROUND

The purpose of this study is to determine if the number and types of patient-reported drug allergies are associated with prosthetic joint infection (PJI) and functional outcomes following total joint arthroplasty (TJA).

METHODS

This is a retrospective review of all patients who underwent a primary, elective total hip (THA) or knee arthroplasty (TKA) over a 10-year period at a single academic institution. Demographic, clinical information, and number and type of patient-reported drug allergy was collected. Univariate and multivariate logistic regressions were performed to identify risk factors for PJI and risk of PJI based on number of allergies. Univariate analysis was also performed to identify if the number of patient-reported allergies affected functional outcome scores.

RESULTS

Of 31,109 patients analyzed, there were 941 (3%) revisions for infection (491 knees and 450 hips). At least one allergy was reported by 16,435 (52.8%) patients, with a mean of 1.2 ± 1.9. Those who underwent revision for infection had a significantly higher number of reported allergies (1.68 ± 1.9 vs 1.23 ± 1.9, P < .0005, 95% confidence interval -0.58 to 0.33). On univariate regression the number of allergies independently predicted revision TJA for infection (P < .0001) as did age, gender, body mass index, and smoking status. On multivariate regression for each additional patient-reported allergy, risk of PJI increased by 1.11 times (95% confidence interval 1.07-1.14, P < .0001). Number of patient-reported allergies did not predict 3-month or 1-year functional outcome scores.

CONCLUSION

Patients with a higher number of reported allergies may be at increased risk of PJI following TJA.

LEVEL OF EVIDENCE

Prognostic Level II.