The Utility of Procalcitonin in Elderly Patients with COPD Exacerbation

OBJECTIVES: To determine the usefulness of Procalcitonin (PCT) in detecting bacterial infection in hospitalized elderly patients with COPD exacerbation. DESIGN: Prospective observational study to compare PCT levels in patients with and without pneumonia. SETTING: Acute care community hospital in United States. PARTICIPANTS: 18 elderly patients age 65 years and older admitted to an internal medicine ward. MEASUREMENTS: Demographic characteristics, general signs and symptoms, laboratory and chest radiographic results, PCT levels, antibiotic use and duration, length of hospital stay and 90-day readmission rates. RESULTS: Eight (44%) patients had a diagnosis of pneumonia. Procalcitonin levels suggestive of a bacterial infection were found in only four patients and each of these patients had pneumonia. Three patients with pneumonia had positive sputum cultures without an elevated PCT level. No patient without pneumonia had an elevated PCT level. The sensitivity and specificity for predicting a bacterial pneumonia in our patients was 50% (95% CI, 16-84%) and 100% (95% CI, 69-100%), respectively. This biomarker had a positive predictive value of 100% (95% CI, 40-100%) and a negative predictive value of 71% (95% CI, 42-91%) CONCLUSION: Our study results suggest that PCT is not sufficiently sensitive to be used as a diagnostic test of bacterial infection in elderly patients with COPD exacerbation. It may assist clinicians in identifying patients without pneumonia who do not require antibiotics due to its high specificity and negative predictive value.