Serum Procalcitonin Level as a Predictor of Bacterial Infection in Patients with COPD Exacerbation

Chronic Obstructive Pulmonary Disease (COPD) is a major cause of mortality and morbidity throughout the world. Although the cause of COPD exacerbations can be bacterial or viral, use of antibiotics in exacerbations remains controversial. Procalcitonin serum level dramatically increases in bacterial infections, but not in viral or noninfectious febrile diseases. The aim of this study is to investigate whether the measurement of procalcitonin can be used to differentiate bacterial from non-bacterial causes of COPD exacerbations.

Sixty-eight COPD patients admitted to the emergency department of Masih Daneshvari Hospital due to COPD exacerbation were studied. At admission and before prescribing antibiotics, we obtained sputum and blood samples for sputum gram staining and culture and measured serum C-reactive protein and procalcitonin. All results were analyzed by SPSS software version 22.

A total of 68 patients including 51 males and 17 females were studied. From 38.2% of patients a respiratory pathogen was isolated from their sputum and 23.5% of patients had elevated serum procalcitonin values. Using Fisher exact test, we found strong correlation between elevated procalcitonin levels above 0.5 ng/ml and sputum culture results (P < 0.01). We also found strong correlation between elevated procalcitonin levels above 0.5 ng/ml with abnormal C-reactive protein levels in a group of patients with positive sputum culture, using Fisher exact test (P <0.01)

As sputum culture and microbiologic studies are time consuming and sometimes expensive, it seems that procalcitonin could be a reliable marker of bacterial infection in COPD exacerbation, although we recommend a larger study with larger sample to consolidate the finding of this study.