SESSION TYPE: Biomarkers in Respiratory Infections
PRESENTED ON: Monday, October 22, 2012 at 11:15 AM - 12:30 PM
PURPOSE: Inappropriate antibiotic usage increases drug resistance, exposes patients to undue side-effects, and drives up healthcare costs. If PCT proves to be a valid biomarker of significant bacterial infection in a military population, one could potentially institute point-of-care algorithms to guide antibiotic management of respiratory infections.
METHODS: This prospective, observational study was developed to determine if a relationship exists amongst PCT levels and clinical diagnosis, infectious etiology, radiographic findings, and disposition in military recruits that present with predefined symptoms of a respiratory infection. Subjects meeting inclusion criteria provide blood for PCT levels and complete blood count, sputum for culture, a throat swab for mRNA expression arrays and protein analysis, and obtain a chest x-ray.
RESULTS: This study is ongoing and set to enroll over 700 subjects of which the first 98 will be presented. PCT levels of healthy controls were in the normal range of < 0.1 ng/ml. Thirty patients (31%) were diagnosed with radiographic proven pneumonia and in subjects with PCT levels greater than 0.25 ng/ml, pneumonia was much more common (p= 0.02). Receiver operating characteristic analysis of PCT for the radiographic diagnosis of pneumonia identified an area under the curve for PCT of 0.66. Of the 79 (81%) patients that had pathogens isolated, rhinovirus (65%) and adenovirus (33%) were the most common isolates and only 8 (7%) subjects have had a bacterial species identified. No correlation has yet to be shown between PCT levels and a specific pathogen. Using solely a previously validated PCT cut-off level > 0.25ng/ml to determine the initiation of antibiotics would have reduced antibiotic use by 86%.
CONCLUSIONS: Procalcitonin levels correlate with pneumonia though further evaluation of its relationship with specific pathogens is needed. Using established PCT algorithms would likely have a utility in reducing antibiotic use and further randomized controlled trials are needed to validate its use.
CLINICAL IMPLICATIONS: PCT algorithms to guide treatment of respiratory illness in military recruits has significant diagnostic and prognostic implications and could substantially reduce antibiotic use and cost.
DISCLOSURE: The following authors have nothing to disclose: J Jonas Carmichael, James Prahl, Massoud Daheshia
Procalcitonin has been approved by the FDA for use in conjunction with other laboratory findings and clinical assessments to assist in the risk assessment of critically ill people for progression to severe sepsis and septic shock. The information provided will be covering the utility of procalcitonin in the diagnosis and management of acute respiratory illness which has been validated in mostly European randomized controlled trials. Naval Medical Center San Diego, San Diego, CA