The clinical usefulness of procalcitonin measurement for assessing the severity of bacterial infection in critically ill patients requiring corticosteroid therapy.

UNLABELLED Markers of inflammation, such as C-reactive protein (CRP) and white blood cell count, have, because of their low specificity, proven far from ideal in identifying patients with sepsis. Procalcitonin (PCT) has been shown to be a useful marker for differentiating patients with bacterial infection from other acute inflammatory conditions. Corticosteroid therapy has been demonstrated to be effective for treating patients with septic shock, late-phase acute respiratory distress syndrome (ARDS), or functional adrenal insufficiency, and the use of corticosteroid in critical illness has recently increased. It is also well established that corticosteroid modulate inflammatory variables in acute inflammatory conditions. The purpose of this study was to evaluate the clinical usefulness of PCT measurement for assessing the severity of bacterial infection in patients requiring corticosteroid therapy. MATERIALS AND METHODS Six patients with confirmed bacterial infectious diseases or suspected infectious diseases and requiring corticosteroid therapy were enrolled in the study. Levels of PCT and CRP were measured. The Sequential Organ Failure Assessment (SOFA) score and the Acute Physiology and Chronic Health Evaluation (APACHE) II score were calculated to evaluate the severity of sepsis. RESULTS 1) There was no significant correlation between the serum concentration of PCT and the plasma level of CRP in patients requiring corticosteroid therapy. 2) The PCT concentration was significantly correlated with the SOFA score (R(2)=0.467, p<0.0001) and the APACHE II score (R(2)=0.308, p=0.0003). However, no significant correlations was found between the CRP concentration and the SOFA score (R(2)=0.054, p=0.15) or the APACHE II score (R(2)=0.043, p=0.20). 3) Data sets were divided into two groups: septic shock and non-septic shock. No significant differences were present in CRP levels between the groups. However, significant differences were apparent in PCT concentrations (p<0.001). CONCLUSION PCT can be a more sensitive and useful marker than CRP for evaluating the severity and progression of sepsis in patients requiring corticosteroid therapy. Further studies are needed to confirm these results in larger groups of patients.