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. 2014 Jul;9(3):162-7.
doi: 10.4103/1817-1737.134072.

Interleukin-6 and procalcitonin as biomarkers in mortality prediction of hospitalized patients with community acquired pneumonia

Ilija Andrijevic  1 , Jovan Matijasevic  1 , Ljiljana Andrijevic  2 , Tomi Kovacevic  1 , Bojan Zaric  1
Affiliations

Interleukin-6 and procalcitonin as biomarkers in mortality prediction of hospitalized patients with community acquired pneumonia

Ilija Andrijevic et al. Ann Thorac Med. 2014 Jul.

Abstract

Introduction: 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.

Keywords: Community acquired pneumonia; interleukin-6; mortality; procalcitonin; risk assessment.

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Conflict of interest statement

Conflict of Interest: The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.

Figures

Figure 1
Figure 1
IL-6 level difference between CAP survivors and lethal outcome, showing significantly higher IL-6 level in deceased patients
Figure 2
Figure 2
Significant postive correlation (Spearman correlation test, Rho = 0.366, P< 0.01) between IL-6 level and PSI; with the elevation of IL-6 PSI significantly rises
Figure 3
Figure 3
Significant positive correlation (Spearman correlation test, Rho = 0.241, P< 0.01) between IL-6 and CURB65; with the elevation of IL-6 CURB65 significantly rises
Figure 4
Figure 4
Significant positive correlation (Spearman correlation test, Rho = 0.360, P< 0.01) between IL-6 and MEWS; with the elevation of IL-6 MEWS significantly rises
Figure 5
Figure 5
ROC curve diagram of IL-6 sensitivity and specificity in prediction of lethal outcome in patients with CAP (AUC ± SE = 0.934 ± 0.035; 95%CI (0.864-1.0); P = 0.000)
Figure 6
Figure 6
ROC curve diagram of PCT sensitivity and specificity in prediction of lethal outcome in patients with CAP (AUC ± SE = 0.667 ± 0.062; 95%CI (0.546-0.789); P = 0. 012)
See this image and copyright information in PMC

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