COMPARISON OF ANTIBIOTIC COSTS AND SELECTION IN HOSPITALIZED PATIENTS WITH A PENICILLIN ALLERGY

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Objective. To compare the antibiotic costs, selection, and duration in hospitalized patients who are labeled as PCNallergic versus non-PCN allergic patients. Background. Penicillin (PCN) and related beta-lactam antimicrobials are the most common cause of drug-induced severe allergic reactions such as anaphylaxis. However, even though the reported incidence of PCN allergy is up to 10%, the true incidence of IgE-mediated hypersensitivity is approximately 0.004% to 0.015%. Consequently, clinicians frequently avoid prescribing PCN and related antibiotics even in situations where a beta-lactam may be the preferred option. Previous studies have suggested that the mean antibiotic cost for patients and duration of therapy was significantly higher in patients with a beta-lactam allergy compared with 75 those without; however, such studies were conducted more than a decade ago and may not reflect current costs. In an effort to minimize antibiotic cost and improve access the preferred antibiotic therapy, various hospitals and institutions have utilized PCN skin testing to identify patients who have an IgE-mediated PCN allergy. Methods. Retrospective review of electronic medical records (EMR) of hospitalized adult patients (18 years and older) who received antibiotics during a 12 month period at St. Mary's Hospital. All patients will be identified using data mining conducted by the hospital's Information Security Director. The electronic medical records will be reviewed by the investigators extracting only the minimal amount of information necessary to conduct the research. Patients will be allocated to either the PCN allergy group or non-PCN allergic group dependent upon the allergies listed in the medical record. Inclusion criteria consisted of hospitalized adult patients aged 18 years and older who were ordered antibiotics for a duration greater than or equal to 24 hours within the 1 year period of August 2012 through July 2013. Patients who were not prescribed antibiotics within the 1 year period; Patients less than 18 years of age; patients who received antibiotics for less than 24 hours; patients who were enrolled in a clinical trial investigating an antibiotic were excluded from the study. Once all data has been extracted, all patient information will be de-identified and assigned a unique ID prior to data analysis. Data collected from EMR includes: patient's age, sex, race, antimicrobial therapy (drug, dose, route, duration), antibiotic allergies, co-morbidities, indication for antibiotic therapy, lengthy of hospitalization, length of ICU stay, number of re-hospitalizations during the 12 month period, number of readmissions (re-hospitalization within 30 days of discharge), APACHE II score, bacteria culture results. The total antimicrobial costs will be calculated based on the drug, dose, formulation, frequency and duration of antimicrobial usage. Student's t-test will be used to compare continuous data such as costs, age, number of antibiotic allergies, number of antibiotics, duration of antibiotic use, length of stay, ICU length of stay, number of re-hospitalizations, number of re-admissions and APACHE II scores. The Chi-square test compared categorical data such as antibiotic allergies, insurance coverage, gender, race, antibiotic class, co-morbidities and antibiotic indications. Results. In-progress. The results of the study may elucidate whether patients with a PCN or beta-lactam allergy receive more costly antibiotics, a greater number of antibiotics or a longer duration of antibiotics. A commercially available skin test can clarify the presence of a true PCN allergy which may facilitate access to cheaper or less broad-spectrum antibiotics with less adverse consequences. These benefits will not directly affect the retrospective subjects but may provide benefit for future care or hospitalizations. Conclusion. In-progress Grants. Unfunded