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Unnecessary beta-lactam avoidance linked to increased risk for adverse events
Patients who did not receive preferred beta-lactam therapy due to a reported drug allergy were more likely to experience adverse events than patients who were treated using beta-lactam antibiotics, according to a trainee-led prospective cohort study.
“Reported allergy to beta-lactam antibiotics is common and often leads to unnecessary avoidance in patients who could tolerate beta-lactam therapy,” Derek R. MacFadden, MD, FRCPC, of the division of infectious diseases, University of Toronto, and colleagues wrote. “In fact, the majority of reported prior reactions are misclassified as allergies; moreover, many individuals with true prior [immunoglobulin E (IgE)]-mediated reactions have loss of hypersensitivity over time.
“Whether or not the risk of allergy from beta-lactam use in some patients reporting allergy is outweighed by the toxicity or potentially inferior efficacy associated with alternate therapies has not been systematically evaluated.”
Researchers at three academic hospitals assessed patient histories (n = 507) for beta-lactam allergies, severity of reactions and preferred therapies. The researchers then retrospectively collected treatment outcomes, recording instances of readmittance for the same infection, Clostridium difficile infections, adverse drug effects and acute kidney injury.
Nineteen percent of patients reported beta-lactam allergies. In 72 (76%) of those patients, beta-lactam therapy was preferred. In the group for whom beta-lactam therapy was preferred, 25 patients (35%) did not receive the treatment, despite only 13 patients (52%) having a history of nonsevere reactions, the researchers reported.
MacFadden and colleagues wrote that patients who did not receive the preferred beta-lactam therapy had a greater risk for adverse events than patients who reported no allergy (adjusted OR = 3.18; 95% CI, 1.28-7.89). Those patients exposed to beta-lactam therapy had a similar risk for adverse events as those who did not report any allergy (aOR = 1.33; 95% CI, 0.62-2.87).
“Our multicenter prospective cohort study suggests that avoidance of preferred beta-lactam therapy in patients who report allergy is associated with an increased risk of adverse events,” MacFadden and colleagues wrote. “Since more than half of patients receiving alternate therapy had nonsevere allergy histories, increasing beta-lactam use in these patients may improve patient outcomes. Development of inpatient programs aimed at accurately identifying beta-lactam allergies … is warranted.”
In an accompanying editorial, researchers wrote that the “vast majority — upwards of 95% — of patients who report an allergy to beta-lactam antibiotics” are more than likely not allergic.
“In the current study, all patients had an allergy history taken, but 35% of beta-lactam ‘allergic’ patients were still not given a beta-lactam when indicated,” Kimberly G. Blumenthal, MD, from the division of rheumatology, allergy, and immunology, Massachusetts General Hospital, and colleagues wrote. “This suggests that it is important to go beyond the allergy history to an assessment and plan informed by well-validated allergy practice and procedures, such as implementation of the penicillin skin test and/or graded challenges (also known as test doses) under medical observation.” – by Andy Polhamus
Disclosure: The researchers report no relevant financial disclosures.