Procalcitonin as a diagnostic marker in acute exacerbation of COPD

Background: Rational prescription of antibiotics in acute exacerbations of COPD (AECOPD) requires predictive markers. Acute phase reactants are capable of demonstrating the inflammation; however, they cannot be employed to make a difference between bacterial and nonbacterial causes of the inflammation. Recently, measurement of procalcitonin (PCT) levels appears to be useful in order to minimize this problem. We aimed to evaluate the diagnostic and prognostic role of procalcitonin in (AECOPD). Patients and methods: A total of 50 patients with AECOPD and 10 of apparently healthy individuals (control group) were studied. On presentation, serum PCT concentrations were measured, and quantitative sputum culture was performed for AECOPD. The patients were reevaluated when they had returned to their stable clinical state. Pathogenic bacterial microorganism (PBM) was only regarded as significant if they reached a growth 105 CFU/ml, indicating the presence of bacterial exacerbation of COPD. The patients were classified into two subgroups: group A included patients with bacterial AECOPD (n = 20), group B included patients with nonbacterial AECOPD (n = 30). Results: On presentation, the levels of PCT for patients of group A (2.69 ± 0.62 ng/mL) were significantly higher than group B (0.07 ± 0.02 ng/mL) and control group (0.05 ± 0.02 ng/mL) (p < 0.001). When they had returned to their stable state, the levels of PCT for patients of group A decreased to (0.06 ± 0.03 ng/mL), which was significantly lower than that in exacerbation (2.69 ± 0.62 ng/mL) (p < 0.001); But in patients of group B compared with exacerbation the levels of PCT did not changed (0.068 ± 0.02 ng/mL) (p > 0.05). In the stable state, there were no differences in the PCT measurement between the two subgroups as well as between patients and control. Furthermore, a significant correlation was recorded between PCT levels in group A at time of presentation and temperature (r = 0.898, p < 0.05), leucocytic count (r = 0.889, p < 0.05), FEV1% of predicted (r = 0.898,p < 0.05), ESR (r = 0.899, p < 0.05), CRP (r = 0.895, p < 0.05) and duration of hospital stay (r = 0.897, p < 0.05). Conclusions: Procalcitonin is a good marker for differentiation between bacterial and nonbacterial AECOPD and could be used to guide antibiotic therapy and reduce antibiotic overuse in hospitalized patients with AECOPD