Utilization of Procalcitonin to Guide Antibiotic Discontinuation in Respiratory Tract Infections in a Community Hospital

Background: Antibiotic overuse leading to increasing antibiotic resistance has been a growing concern. Patients presenting with acute respiratory tract infections (RTI) are often started empirically on antibiotics and continued for days, unless confirmatory results are reported by microbiological testing. Procalcitonin is a serum inflammatory marker that increases in bacterial infections and is utilized as an adjunct to help differentiate viral versus bacterial pneumonia. Procalcitonin-guided management is associated with significantly lower antibiotic exposure and mortality. No studies exist in literature that assess the appropriate utilization of negative procalcitonin test for antibiotic discontinuation. This study assesses utilization of a negative PCT (<0.25 ng/ml) to guide antibiotic discontinuation in patients with pneumonia in a community hospital. Methods:Retrospective observational study including adult patients admitted to our community hospital in 1 year (July 2019-June 2020) with diagnosis of community acquired pneumonia and started on empiric antibiotic therapy and had procalcitonin levels checked. Our hypothesis was that PCT is not being appropriately used for discontinuation of antibiotics and that rate of discontinuation of antibiotics will be less despite a negative PCT. Statistical analysis was performed using XLSTAT. Categorical variables were represented by frequencies and proportions and compared using Chi-square and z test for two proportions. Results: 516 charts were reviewed. After excluding missing data, 176 patients were included. 100 patients had negative PCT. Antibiotics were discontinued in 16% of patients with negative PCT, compared to 58% (p<0.0001), in whom antibiotics were continued without any other indication (including UTI, severe COPD exacerbation, COVID pneumonia) despite a negative PCT. The difference between the percentage of antibiotic discontinuation in our PCT guided treatment sample (9%, n=16/176) was also found to be statistically significant (p< 0.001) compared to percentage of antibiotic discontinuation in population using data from a meta-analysis of 7 RCTs (42%, n=698/1658).1 Conclusion:Previous studies have shown that procalcitonin guided treatment aids in decreasing antibiotic exposure. In lower respiratory tract infections, clinicians order PCT test to aid in differentiating viral versus bacterial etiology and ultimately help guide antibiotic therapy. Our data analysis reveals that despite negative PCT, thus indicating a likely viral etiology, clinicians are not consistently making changes to empiric antibiotic use. This study addresses need for further recommendations from antibiotic stewardship programs regarding procalcitonin-guided antibiotic use and prevent unnecessary ordering of PCT test.