Impact of Beta-Lactam Allergies on Selection of Antimicrobials in an Inpatient Setting Among Veteran Population

Beta-lactam antibiotics are among the most common and widely used antibiotics. However, reported allergy to this class of antibiotics is also common, leading to the use of alternative broad-spectrum antibiotics by healthcare providers. This has led to the emergence of various negative health outcomes. The purpose of the study is to investigate the impact of using alternative antibiotics secondary to a beta-lactam allergy among U.S. veterans who have otherwise multiple comorbidities.

This retrospective observational analysis was conducted over a 5-year period (January 1, 2011 to December 31, 2016) at the Memphis Veterans Affairs Medical Center (VAMC). Admitted patients with a documented beta-lactam allergy were categorized to preferred or non-preferred status based on initial antibiotic therapy antibiotic, allergy history, published guidelines, and local antibiogram. Preferred therapy was defined as the optimal antibiotic treatment for a given indication based on patient allergy history, published Infectious Disease Society of America guidelines, and local antibiogram of Memphis VAMC. The therapy was classified as "non-preferred" if it did not satisfy the preferred therapy criteria. Non-preferred treatments were further assessed for appropriateness based on indication and patient-specific factors. Chi-square and Fisher's exact tests were conducted to find a difference in rates of negative sequelae among patients receiving preferred vs. non-preferred treatments and appropriate vs. inappropriate treatments.

Of the 1806 admissions identified, data were collected on 95 unique patients with 147 different antibiotic regimens. There were 68 (52%) preferred treatment regimens and 64 (48%) non-preferred treatment regimens. Of the 64 non-preferred treatments, 43 (67%) were inappropriate. There was a statistically significant decrease in the number of adverse drug events and in the combined negative sequelae outcome among patients receiving preferred therapy vs. non-preferred therapy (2 vs. 12; P < .01 and 11 vs. 23; P < .01, respectively).

The receipt of non-preferred antibiotic therapy among veterans with a recorded beta-lactam allergy may be associated with an increased risk of developing negative outcomes. Among military personnel, removing unnecessary beta-lactam allergies would improve readiness with optimal antibiotic choices and avoidance of unnecessary risks, expediting return to full duty.