The role of procalcitonin in predicting severity and clinical course of aspiration pneumonia

Background: Procalcitonin (PCT) is known as a useful diagnostic marker signifying bacterial infection and its serum levels correlate with disease severity measured by scoring systems such as pneumonia severity index (PSI) or Age, Dehydration, Respiratory failure, Orientation disturbance, Pressure (A-DROP) score, a Japanese prognostic scale for community-acquired pneumonia (CAP). However, for aspiration pneumonia, a major cause of death among elderly patients, little is known about the role of PCT. Objective: We investigated whether PCT levels would be useful for predicting severity and clinical course of aspiration pneumonia. Method: We conducted a prospective study in 49 patients with aspiration pneumonia who were admitted to our hospital from September 2013 and April 2014. Patients with immunosuppression or on treatment with chemotherapy were excluded. We analyzed the association between PCT levels on admission and PSI and A-DROP scores. In addition, correlation between PCT levels and the duration of administration of intravenous antimicrobial agents as an indicator of clinical course was examined. Results: The mean age of patients was 85 years and 25 (51%) were male. PCT levels did not correlate with PSI risk classification (correlation coefficient (R):0.25, p=0.08) nor A-DROP scores (R: 0.20, p=0.17). A multiple regression analysis showed no association between PCT levels on admission and the number of days of intravenous antimicrobial agent administration (regression coefficient (β): 1.59, 95%CI -0.8 to 4.0, p=0.19). Conclusions: PCT levels were not useful for predicting severity and clinical course of aspiration pneumonia, in contrast to previous reports of CAP.