title: Interleukin-6 and procalcitonin as biomarkers in mortality prediction of hospitalized patients with community acquired pneumonia.
abstract: BACKGROUND
  Community acquired pneumonia (CAP) may present as life-threatening infection with uncertain progression and outcome of treatment. Primary aim of the trial was determination of the cut-off value of serum interleukin-6 (IL-6) and procalcitonin (PCT) above which, 30-day mortality in hospitalized patients with CAP, could be predicted with high sensitivity and specificity. We investigated correlation between serum levels of IL-6 and PCT at admission and available scoring systems of CAP (pneumonia severity index-PSI, modified early warning score-MEWS and (Confusion, Urea nitrogen, respiratory rate, Blood pressure, ≥65 years of age-CURB65).
  
  
  METHODS
  This was prospective, non-randomized trial which included 101 patients with diagnosed CAP. PSI, MEWS and CURB65 were assessed on first day of hospitalization. IL-6 and PCT were also sampled on the first day of hospitalization.
  
  
  RESULTS
  Based on ROC curve analysis (AUC ± SE = 0.934 ± 0.035; 95%CI(0.864-1.0); P = 0.000) hospitalized CAP patients with elevated IL-6 level have 93.4% higher risk level for lethal outcome. Cut-off value of 20.2 pg/ml IL-6 shows sensitivity of 84% and specificity of 87% in mortality prediction. ROC curve analysis confirmed significant role of procalcitonin as a mortality predictor in CAP patients (AUC ± SE = 0.667 ± 0.062; 95%CI(0.546-0.789); P = 0.012). Patients with elevated PCT level have 66.7% higher risk level for lethal outcome. As a predictor of mortality at the cut-off value of 2.56 ng/ml PCT shows sensitivity of 76% and specificity of 61.8%.
  
  
  CONCLUSIONS
  Both IL-6 and PCI are significant for prediction of 30-day mortality in hospitalized patients with CAP. Serum levels of IL6 correlate with major CAP scoring systems.
authors.affiliation: Institute for Pulmonary Diseases of Vojvodina, Clinical Trials Unit, Faculty of Medicine, University of Novi Sad, Serbia.
authors.forename: Ilija
authors.initials: I
authors.lastname: Andrijevic
authors.affiliation: Institute for Pulmonary Diseases of Vojvodina, Clinical Trials Unit, Faculty of Medicine, University of Novi Sad, Serbia.
authors.forename: Jovan
authors.initials: J
authors.lastname: Matijasevic
authors.affiliation: Institute of Oncology, Faculty of Medicine, University of Novi Sad, Serbia.
authors.forename: Ljiljana
authors.initials: L
authors.lastname: Andrijevic
authors.affiliation: Institute for Pulmonary Diseases of Vojvodina, Clinical Trials Unit, Faculty of Medicine, University of Novi Sad, Serbia.
authors.forename: Tomi
authors.initials: T
authors.lastname: Kovacevic
authors.affiliation: Institute for Pulmonary Diseases of Vojvodina, Clinical Trials Unit, Faculty of Medicine, University of Novi Sad, Serbia.
authors.forename: Bojan
authors.initials: B
authors.lastname: Zaric
keywords: Community acquired pneumonia; interleukin-6; mortality; procalcitonin; risk assessment