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Suboptimal Antibiotic Prescribing May Be Common for Patients with Documented Penicillin Allergy

Key findings

  • In this database study of 10,992 inpatients receiving antibiotics at 106 U.S. hospitals, 16% had a penicillin allergy noted in their medical record
  • Compared with patients who had no penicillin allergy noted, those with a documented penicillin allergy had 94% higher odds of receiving a ß-lactam alternative and 65% lower odds of receiving a narrow-spectrum ß-lactam antibiotic
  • The largest increased odds of a ß-lactam alternative were for clindamycin (adjusted OR, 5.34), which increases the risk of Clostridium difficile infection
  • Patients who needed an antibiotic as prophylaxis for surgery were at particularly high risk of receiving a ß-lactam alternative antibiotic (aOR, 7.31) and particularly low risk of receiving a narrow-spectrum ß-lactam antibiotic (aOR, 0.11)
  • Inpatient penicillin allergy evaluations are most important for patients who would otherwise be prescribed clindamycin and those scheduled for a surgical procedure

In a 2019 JAMA review, researchers at Massachusetts General Hospital found that more than 10% of hospitalized patients who receive antibiotics have a penicillin allergy noted in their medical record, but allergy evaluation with or without diagnostic testing disproves more than 90% of those allergies.

The goals of antimicrobial stewardship are undermined when a reported allergy to penicillin leads to the use of a broad-spectrum antibiotic that increases the risk of antimicrobial resistance. In addition, broad-spectrum antibiotics increase the risk of Clostridium difficile infection.

Rochelle Walensky, MD, MPH, chief, Division of Infectious Diseases, and Kimberly G. Blumenthal, MD, MSc, co-director of the Clinical Epidemiology Program in the Division of Rheumatology Allergy and Immunology at Mass General, and colleagues have conducted the first study of the inpatient prevalence of penicillin allergies that involved more than one hospital or health care system. In a research letter published in JAMA Internal Medicine, they report that substantial numbers of inpatients with supposed penicillin allergies are treated with alternatives that may be inferior and/or associated with adverse drug events.

Study Details

The researchers used a nationwide commercial database to identify 10,992 patients who received antibiotics at 106 U.S. acute care hospitals between September 2018 and January 2019. 1,741 patients (16%) had a penicillin allergy noted.

Antibiotic Use Overall

Compared with patients who had no penicillin allergy noted, patients with a documented penicillin allergy had:

  • Increased odds of receiving a β-lactam alternative antibiotic (adjusted OR, 1.94), with especially high odds of clindamycin use (aOR, 5.34)
  • Lower odds of receiving a narrow-spectrum β-lactam antibiotic (aOR, 0.35)

Antibiotic Use by Indication

The association between documented penicillin allergy and β-lactam alternative antibiotic use was stronger among patients whose indication was:

  • Urinary tract infection (aOR, 2.07)
  • Prophylaxis for surgery (aOR, 7.31)

The association between documented penicillin allergy and narrow-spectrum β-lactam antibiotic use was stronger among patients whose indication was:

  • Pneumonia (aOR, 0.31)
  • Urinary tract infection (aOR, 0.26)
  • Prophylaxis for surgery (aOR, 0.11)

Applying the Results

The Infectious Diseases Society of America and the Society for Healthcare Epidemiology of America jointly recommend inpatient penicillin allergy evaluations as part of antibiotic stewardship. The PEN-FAST test, which considers allergy history, is one option for hospitals that lack the resources for routine allergist consultations.

This study suggests that inpatient penicillin allergy evaluations, with or without formal testing, are most important for patients who would otherwise be prescribed clindamycin and those scheduled for a surgical procedure.

94%
higher odds of receiving a β-lactam alternative antibiotic among patients who had a penicillin allergy noted in their chart compared with those who did not

65%
lower odds of receiving a narrow-spectrum β-lactam antibiotic among patients who had a penicillin allergy noted in their chart compared with those who did not

7x
higher odds of receiving a β-lactam alternative antibiotic among patients who had a penicillin allergy noted in their chart when the indication was prophylaxis for surgery

89%
lower odds of receiving a narrow-spectrum β-lactam antibiotic among patients who had a penicillin allergy noted in their chart when the indication was prophylaxis for surgery

Learn more about the Division of Rheumatology, Allergy and Immunology at Mass General

Refer a patient to the Rheumatology Unit

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