1992. Initial Procalcitonin Level and Antibiotic Practice Patterns Among Patients with Acute Respiratory Infections

BACKGROUND: The utility of procalcitonin (PCT)-guided algorithms to decrease antibiotic use has been extensively studied in clinical trials. The guidance that PCT provides as it translates into real-world practice is unclear. This study aims to describe real-world antibiotic prescribing practices in relation to PCT in patients admitted to our US-based health system with acute respiratory infections. METHODS: Retrospective cohort study of 1,606 adults admitted within our US health system from January 1, 2016 to December 31, 2018 with a primary diagnosis of acute upper or lower respiratory infection with at least one PCT measurement. Antibiotic practice patterns were evaluated using pharmacy analytic information and antibiotic status to note antibiotics given prior to and 36 hours after PCT result. Analysis of discordance with initial PCT level was defined as continuing or starting antibiotics after a low PCT level (PCT ≤0.25 μg/L) and withholding or discontinuing antibiotics after a high PCT level (PCT > 0.25 μg/L). RESULTS: Antibiotic prescription patterns after the result of initial PCT level are summarized in Table 1. Only 242 patients (15%) had more than one PCT-level checked. Overall, antibiotic discordance with initial PCT result was 45%; mostly attributed to continuing or starting antibiotics despite a low PCT level (77%). (Figure 1) There were 496 patients who were initially started and continued on antibiotics despite a low PCT result. Of this subgroup, only one patient had a serial PCT measured, and 12 were admitted for Chronic Obstructive Pulmonary Disease (COPD) exacerbation and continued on azithromycin/doxycycline after result of the low PCT. CONCLUSION: Utilization of antibiotics went against well-studied PCT cutoffs 45% of the time, primarily driven by antibiotic use at low PCT levels. Only a small number were continued on azithromycin/doxycycline for anti-inflammatory effect in COPD exacerbations, indicating that most patients received antibiotics for presumed bacterial infection despite the high negative predictive value of PCT. This study illustrates PCT use in real-world practice did not significantly alter prescribing practices, potentially from lack of confidence or knowledge in interpreting PCT results and lack of serial measurements to aid in decision-making. [Image: see text] [Image: see text] DISCLOSURES: All authors: No reported disclosures.