PSP and NT-proCNP assessed for predisposition to infection

Abstract

Gouel-Cheron and colleagues have recently published a pilot study [1] on which we would like to offer the following comments. As the paper currently appears, it is unclear whether in fact the study aimed at evaluating the predictive value of pancreatic stone protein/regenerating protein (PSP) and amino-terminal pro-C-type natriuretic peptide (NT-proCNP) for a predisposition to infection in non-infected systemic inflammatory response syndrome (SIRS) trauma patients under mechanical ventilation, or whether it rather aimed at evaluating the predictive value (that is, prognosis) of the biomarkers for sepsis development. Indeed, the authors omitted to mention that the assessment was carried out in patients exclusively before the occurrence of a hospital-acquired infection. This certainly explains why there are only 16 patients plotted in Figure 1 and not 21 (36% of 61 patients) as one would have otherwise expected. A non-equivocal use of 'prediction' is therefore essential. Providing these indications would have allowed to put the results into perspective with recent studies published in Critical Care on PSP ability to differentiate patients with sepsis from those with a non-infective SIRS [2] or on NT-proCNP ability to confirm sepsis and correlate with markers of bacterial infection [3]. Instead of analyzing the role of PSP and NT-proCNP in the prediction of sepsis, the authors seem to have actually predicted future hospital-acquired infection in the intensive care unit. Stating that the study assesses the prediction of sepsis is therefore clearly a misleading shortcut, since in fact the occurrence of infection, sometime later than the time-point of analysis of the biomarkers, will classify these SIRS patients as septic by definition.