Procalcitonin for diagnosis of bacterial pneumonia in critically ill patients during 2009 H1N1 influenza pandemic: a prospective cohort study, systematic review and individual patient data meta-analysis

Abstract

IntroductionProcalcitonin (PCT) is helpful for diagnosing bacterial infections. The diagnostic utility of PCT has not been examined thoroughly in critically ill patients with suspected H1N1 influenza.MethodsClinical characteristics and PCT were prospectively assessed in 46 patients with pneumonia admitted to medical ICUs during the 2009 and 2010 influenza seasons. An individual patient data meta-analysis was performed by combining our data with data from five other studies on the diagnostic utility of PCT in ICU patients with suspected 2009 pandemic influenza A(H1N1) virus infection identified by performing a systematic literature search.ResultsPCT levels, measured within 24 hours of ICU admission, were significantly elevated in patients with bacterial pneumonia (isolated or coinfection with H1N1; n = 77) (median = 6.2 μg/L, interquartile range (IQR) = 0.9 to 20) than in patients with isolated H1N1 influenza pneumonia (n = 84; median = 0.56 μg/L, IQR = 0.18 to 3.33). The area under the curve of the receiver operating characteristic curve of PCT was 0.72 (95% confidence interval (CI) = 0.64 to 0.80; P < 0.0001) for diagnosis of bacterial pneumonia, but increased to 0.76 (95% CI = 0.68 to 0.85; P < 0.0001) when patients with hospital-acquired pneumonia and immune-compromising disorders were excluded. PCT at a cut-off of 0.5 μg/L had a sensitivity (95% CI) and a negative predictive value of 80.5% (69.9 to 88.7) and 73.2% (59.7 to 84.2) for diagnosis of bacterial pneumonia, respectively, which increased to 85.5% (73.3 to 93.5) and 82.2% (68.0 to 92.0) in patients without hospital acquired pneumonia or immune-compromising disorder.ConclusionsIn critically ill patients with pneumonia during the influenza season, PCT is a reasonably accurate marker for detection of bacterial pneumonia, particularly in patients with community-acquired disease and without immune-compromising disorders, but it might not be sufficient as a stand-alone marker for withholding antibiotic treatment.

Perioperative White Blood Cell Count as a Marker for Patient and Graft Survival after Orthotopic Liver Transplantation

“…In contrast, PCT is produced in C cells of the thyroid gland and by neuroendocrine cells of the lung and the intestine [12,13]. However, PCT is more a marker for bacterial than for viral infections [14][15][16]. Furthermore, it is possible that we here did not detect any statistical significance because the maximal increase of PCT might be at a later than fours days after OLT.…”

The diagnostic accuracy of procalcitonin for bacteraemia: a systematic review and meta-analysis

“…Some meta-analyses focused on the diagnostic value of procalcitonin for microbiologically confirmed local infection [28][29][30][31][32][33][34][35][36][37][38][39] or bacteraemia [40]. However, the number of included studies was small, specific patient subgroups were analysed or studies concerning sepsis were included as well [28][29][30][31][32][33][34][35][36][37][38][39][40].…”

Co-infection in severe influenza: a new epidemiology?

“…Given the high probability of bacterial co-infection in these patients, its association with mortality, and the fact that delaying antimicrobial treatment could be associated with even higher mortality [16], the empiric use of antimicrobial treatment in such patients should be encouraged. Although some biomarkers (and in particular procalcitonin) have been shown to be associated with bacterial co-infection in this setting, their accuracy is not sufficient to determine initiation of antimicrobial treatment [17]. Procalcitonin may be helpful in this setting as a marker to stop antimicrobial treatment in patients without proven infection and/or low procalcitonin level [18].…”