Penicillin Allergy Delabeling Can Decrease Antibiotic Resistance, Reduce Costs, and Optimize Patient Outcomes
Background: Antibiotics are one of the most frequently prescribed medications. Among all classes of antibiotics, penicillins are prescribed due to their clinical efficacy, cost-effectiveness, and general safety. Unfortunately, penicillins also are the most common drug allergy listed in patient medical records. Increasing evidence shows that > 90% of patients labeled with a penicillin allergy are not allergic to penicillins and associated β -lactams. The health care consequences of penicillin allergy in the setting of military medicine and readiness are important to consider.
Observations: In the US, 8 to 10% of the population and up to 15% of hospitalized patients have a documented penicillin allergy, limiting the use of these effective antibiotics. When treating a patient with a penicillin allergy, many clinicians avoid prescribing all β -lactam antibiotics and stay away from cephalosporins due to the concern for potential cross-reactivity. The cost of treating those with a documented penicillin allergy is greater than the cost for those who can receive penicillin, as treatment with broad-spectrum antibiotics often results in longer hospitalizations with increased rates of adverse effects (AEs). Despite preventive programs such as vaccinations, hygiene measures, and prophylactic antibiotics, military personnel are at increased risk for infections due to the military’s mobile nature and crowded living situations.
Conclusions: Many patients report an allergy to penicillin, but only a small portion have a true immune-mediated allergy. Given the clinical, public health, and economic costs associated with a penicillin allergy label, evaluation and clearance of penicillin allergies improves clinical outcomes, decreases AEs from higher risk alternative broad-spectrum antibiotics, and prevents the spread of antibiotic resistance. In military personnel, penicillin delabeling improves readiness with optimal antibiotic options and avoidance of unnecessary risks, expediting return to full duty.
Cost of Penicillin Allergies
Penicillin allergy plays an important role in rising health care costs. In 2017, health care spending reached 17.9% of the gross domestic product.22 Macy and Contreras demonstrated the significantly higher costs associated with having a reported (and unverified) penicillin allergy in a matched cohort study. Inferred for the extra hospital use, the penicillin allergy group cost the health care system $64,626,630 more than for the group who did not have a penicillin allergy label.7 A subsequent study by Macy and Contreras of both inpatient and outpatient settings showed a potential savings of $2,000 per patient per year in health care expenses with the testing and delabeling of penicillin allergies.23 Use of newer and broad-spectrum antibiotics also are more costly and contribute to higher health care costs.24
When these potential savings are applied to the military insurance population of 9.4 million beneficiaries (TRICARE, including active duty, their dependents, and all retirees participating in the program), the results showed that this could impart a savings of nearly $1.7 billion annually, using the model by Macy and Contreras.23,25,26
Previously with colleagues, I reviewed penicillin’s role in military history, compiled data from relevant studies from military penicillin allergy rates and delabeling efforts, and calculated the potential economic impact of penicillin allergies along with the benefits of testing.26 Calculations were estimated using the TRICARE beneficiary population (9.4 million) × the estimated prevalence (10%) to get an estimate of 940,000 TRICARE patients with penicillin allergy in their medical record.25 If 90% of those patients were delabeled, this would equal 846,000 TRICARE patients. When multiplied by the potential savings of $2,000 per patient per year, the estimated savings would be $1,692,000,000 annually.23,26
Current literature provides compelling evidence that all health care plans should use penicillin allergy testing and delabeling programs.3,23,26 As most patients with a history of penicillin allergy in their medical records do not have a verified allergy, delabeling those who do not have a true allergy will have individual, public health, and cost benefits.3,7,23,26
Antibiotic Stewardship
Antibiotic stewardship programs are now mandated to combat antibiotic resistance.3,27 This program is supported by major medical organizations, including the Centers for Disease Control and Prevention, Society for Healthcare Epidemiology of America, Infectious Disease Society of America, and the American Academy of Allergy Asthma and Immunology.3 Given the role of broad-spectrum antibiotics in antibiotic resistance, penicillin allergy testing and delabeling is an important component of these programs.3
In the US, > 2 million people acquire antibiotic resistant infections annually; 23,000 people die of these infections.27 More than 250,000 illnesses and 14,000 deaths annually are due to C difficile.27 There are many factors contributing to the increase in antibiotic resistance; however, one established and consistent factor is the use of broad-spectrum antibiotics. Further, broad-spectrum antibiotics are often used when first-line agents, such as penicillins, cannot be used due to a reported “allergy.” In addition, there are fewer novel antibiotics being developed, and as they are introduced, pathogens develop resistance to these new agents.27
