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

Optimizing Cefazolin Prophylaxis in Obstetrical Patients with Reported Beta-Lactam Allergy Undergoing Cesarean Delivery

OBJECTIVE

Evaluate the impact of an allergy history guided algorithm for optimizing peri-operative cefazolin use in patients with reported beta-lactam allergy undergoing cesarean delivery.

METHODS

The Allergy Clarification for Cefazolin Evidence-based Prescribing Tool (ACCEPT) was developed through consensus by allergists, anesthesiologists and infectious diseases specialists, and implemented over a two-month period (December 1, 2018 to January 31, 2019). A segmented regression on monthly cefazolin use was conducted during the baseline (January 1 to November 30, 2018) and intervention (February 1 to December 31, 2019) periods to evaluate the impact of ACCEPT on the monthly use of peri-operative cefazolin in patients with reported beta-lactam allergy undergoing cesarean delivery. The frequency of peri-operative allergic reactions and surgical site infections were collected during both periods.

RESULTS

Of the 3128 eligible women who underwent a cesarean delivery, 282 (9%) reported a beta-lactam allergy. The most common beta-lactam allergens were penicillin (64.3%), amoxicillin (16.0%), and cefaclor (6.0%). The most frequently reported allergic reactions were rash (38.1%), hives (21.4%), and unknown (11.6%). Use of cefazolin increased from 52% (baseline) to 87% during the intervention period. Segmented regression analysis confirmed a statistically significant increase following implementation (incidence rate ratio 1.62, 95% CI 1.19 - 2.21, p=0.002). There was one perioperative allergic reaction in the baseline period and two during the intervention period. Cefazolin use remained high (92%) two years after algorithm implementation.

CONCLUSIONS

Implementation of a simple allergy history guided algorithm in obstetrical patients with reported beta-lactam allergy resulted in a sustained increase in peri-operative cefazolin prophylaxis.

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.

Antibiotic Prescriptions among China Ambulatory Care Visits of Pregnant Women: A Nationwide Cross-Sectional Study

BACKGROUND

Antibiotic use in pregnant women at the national level has rarely been reported in China.

OBJECTIVES

We aimed to investigate antibiotic prescriptions during pregnancy in ambulatory care settings in China.

METHODS

Data of 4,574,961 ambulatory care visits of pregnant women from October 2014 to April 2018 were analyzed. Percentages of Antibiotic prescriptions by different subgroups and various diagnosis categories and proportions of inappropriate antibiotic prescriptions for different subgroups were estimated. Food and Drug Administration (FDA) pregnancy categories were used to describe the antibiotic prescription patterns. The 95% confidence intervals (CIs) were estimated using the Clopper--Pearson method or Goodman method.

RESULTS

Among the 4,574,961 outpatient visits during pregnancy, 2.0% (92,514 visits; 95% CI, 2.0-2.0%) were prescribed at least one antibiotic. The percentage of antibiotic prescriptions for pregnant women aged >40 years was 4.9% (95% CI, 4.7-5.0%), whereas that for pregnant women aged 26-30 years was 1.5% (95% CI, 1.4-1.5%). In addition, percentages of antibiotic prescriptions varied among different trimesters of pregnancy, which were 5.4% (95% CI, 5.3-5.4%) for the visits in the first trimester of pregnancy and 0.5% (95% CI, 0.4-0.5%) in the third trimester of pregnancy. Furthermore, the percentages of antibiotic prescriptions substantially varied among different diagnosis categories and nearly three-quarters of antibiotic prescriptions had no clear indications and thus might be inappropriate. In total, 130,308 individual antibiotics were prescribed; among these, 60.4% (95% CI, 60.0-60.8%) belonged to FDA category B, 2.7% (95% CI, 2.1-3.5%) were classified as FDA category D and 16.8% (95% CI, 16.2-17.4%) were not assigned any FDA pregnancy category.

CONCLUSIONS

Antibiotic prescriptions in ambulatory care during pregnancy were not highly prevalent in mainland China. However, a substantial proportion of antibiotics might have been prescribed without adequate indications. Antibiotics whose fetal safety has not been sufficiently illustrated were widely used in pregnant women.

Assessment of the Frequency of Dual Allergy to Penicillins and Cefazolin: A Systematic Review and Meta-analysis

Importance

Cefazolin is the preoperative antibiotic of choice because it is safer and more efficacious than second-line alternatives. Surgical patients labeled as having penicillin allergy are less likely to prophylactically receive cefazolin and more likely to receive clindamycin or vancomycin, which results in higher rates of surgical site infections.

Objective

To examine the incidence of dual allergy to cefazolin and natural penicillins.

Data Sources

MEDLINE/PubMed, Web of Science, and Embase were searched without language restrictions for relevant articles published from database inception until July 31, 2020.

Study Selection

In this systematic review and meta-analysis, a search of MEDLINE/PubMed, Web of Science, and Embase was performed for articles published from database inception to July 31, 2020, for studies that included patients who had index allergies to a natural penicillin and were tested for tolerability to cefazolin or that included patients who had index allergies to cefazolin and were tested for tolerability to a natural penicillin. A total of 3228 studies were identified and 2911 were screened for inclusion.

Data Extraction and Synthesis

Data were independently extracted by 2 authors. Bayesian meta-analysis was used to estimate the frequency of allergic reactions.

Main Outcomes and Measures

Dual allergy to cefazolin and a natural penicillin.

Results

Seventy-seven unique studies met the eligibility criteria, yielding 6147 patients. Cefazolin allergy was identified in 44 participants with a history of penicillin allergy, resulting in a dual allergy meta-analytical frequency of 0.7% (95% credible interval [CrI], 0.1%-1.7%; I2 = 74.9%). Such frequency was lower for participants with unconfirmed (0.6%; 95% CrI, 0.1%-1.3%; I2 = 54.3%) than for those with confirmed penicillin allergy (3.0%; 95% CrI, 0.01%-17.0%; I2 = 88.2%). Thirteen studies exclusively assessed surgical patients (n = 3884), among whom 0.7% (95% CrI, 0%-3.3%; I2 = 85.5%) had confirmed allergy to cefazolin. Low heterogeneity was observed for studies of patients with unconfirmed penicillin allergy who had been exposed to perioperative cefazolin (0.1%; 95% CrI, 0.1%-0.3%; I2 = 13.1%). Penicillin allergy was confirmed in 16 participants with a history of cefazolin allergy, resulting in a meta-analytical frequency of 3.7% (95% CrI, 0.03%-13.3%; I2 = 64.4%). The frequency of penicillin allergy was 4.4% (95% CrI, 0%-23.0%; I2 = 75%) for the 8 studies that exclusively assessed surgical patients allergic to cefazolin.

Conclusions and Relevance

These findings suggest that most patients with a penicillin allergy history may safely receive cefazolin. The exception is patients with confirmed penicillin allergy in whom additional care is warranted.

Penicillin Allergy Assessment in Pregnancy: Safety and Impact on Antibiotic Use

BACKGROUND

Penicillin and other beta-lactam antibiotics are recommended for group B Streptococcus and cesarean section prophylaxis, but approximately 10% of pregnant patients report a penicillin allergy.

OBJECTIVE

To assess the safety and impact of penicillin allergy evaluation in pregnant patients.

METHODS

In this retrospective study of obstetrician-ordered Allergy/Immunology (AI) electronic consultations (e-consults) from September 20, 2017 through December 31, 2019, we reviewed the electronic health record for e-consult recommendation; patient demographic, obstetric, and allergy histories; and peripartum antibiotic utilization with indication. For patients whose electronic consultation recommended an in-person AI evaluation, testing outcomes were determined, and multivariable logistic regression models were used to compare antibiotic use between patients who did and did not receive an in-person AI evaluation.

RESULTS

Of 389 obstetrician-ordered e-consults, 363 (93%) recommended an in-person AI evaluation; of these, 222 (61%) patients received an in-person AI evaluation. Of 220 (99%) patients skin tested, 209 (95%) had their penicillin allergy label safely removed. Compared with patients who did not receive an in-person AI evaluation despite it being recommended (n = 141), patients with in-person AI evaluation (n = 222) had reduced peripartum vancomycin (adjusted odds ratio [aOR], 0.07; 95% CI, 0.01-0.33), clindamycin (aOR, 0.17; 95% CI, 0.08-0.34), and gentamicin (aOR, 0.39; 95% CI, 0.19-0.78) use and increased penicillin (aOR, 18.0; 95% CI, 6.30-51.2) use. The fully AI evaluated patients had increased first-line antibiotic prophylaxis for group B Streptococcus (aOR, 26.9; 95% CI, 6.32-114) and cesarean section (aOR, 1.94; 95% CI, 1.06-3.52).

CONCLUSIONS

In a sample of 220 pregnant patients with penicillin allergy histories and in-person AI evaluation, penicillin allergy testing was safe and associated with significantly reduced broad-spectrum antibiotic use and increased first-line beta-lactam antibiotic use.