Title:
[Significance of serum procalcitonin levels in the evaluation of severity and prognosis of patients with systemic inflammatory response syndrome].

Abstract:
To observe the dynamic changes in serum procalcitonin (PCT), C-reactive protein (CRP), and white blood cell (WBC) count in systemic inflammatory response syndrome (SIRS) and their implication in assessment of illness severity and prognosis.
A prospective case control study was conducted. Seventy-two patients with SIRS in Guangdong General Hospital were enrolled in intensive care unit (ICU) from May, 2010 to June, 2011. Parameters including PCT, CRP, and WBC count were determined on the 1st, 3rd, and 5th day after admission. The patients were divided into septic group (n=49) and non-septic group (non-infectious SIRS group, n=23) according to the presence or absence of infectious. Dynamic changes in all parameters were compared between the two groups and correlation analysis was carried out on the basis of differential indexes and sequential organ failure assessment (SOFA). The clinical outcome within 28 days after admission to ICU was observed, and the patients were divided into death group (n=19) and survival group (n=53). Dynamic changes in all parameters between the two groups were compared. Relevant parameters were analyzed with area under receiver operator characteristic curve (ROC curve, AUC) to predict 28-day survival. Logistic regression analysis of the multiple factors was used to screen independent risk factors for predicting death.
PCT level (μg/L) on 1st, 3rd, 5th day after admission were all significantly higher in septic group than those in non-septic group (1st day: 2.5±0.3 vs. 0.9±0.2, 3rd day: 1.9±0.3 vs. 0.6±0.2, 5th day: 0.9±0.1 vs. 0.5±0.1, all P<0.05), while there was no statistically significant difference in CRP and WBC between two groups. PCT level in septic group was gradually decreased with time, there were statistically significant differences between septic group and non-septic group at the different treatment time (all P<0.05), but there was no correlation between PCT and treatment duration in non-septic group. Positive statistical correlation was found between PCT and SOFA score (r=0.979, P<0.05). PCT (μg/L) and CRP levels (mg/L) on 1st, 3rd, 5th day were significantly higher in death group than those of survival group (PCT on 1st day: 2.0±0.8 vs. 0.8±0.3, 3rd day: 2.2±0.7 vs. 0.6±0.3, 5th day: 2.4±1.0 vs. 0.4±0.1; CRP on 1st day: 422±45 vs. 411±44, 3rd day: 418±39 vs. 403±52, 5th day: 392±38 vs. 382±46, all P<0.05), but WBC count showed no statistically significant difference between two groups. PCT level in survival group showed a significant lowering along with treatment duration, and statistical difference was seen by paired comparison between every two time-points (all P<0.05). There was no correlation between PCT level and treatment duration in death group, and it maintained a rather high level. No significant difference was seen in CRP and WBC between two groups with passage of time. AUC was 0.824 and 0.720, respectively, when patient's 28-day survival was predicted by PCT and CRP (both P<0.01). Logistic regression analysis of the multiple factors revealed that PCT>2.23 μg/L was independent risk factor predicting the prognosis [odds ratio (OR) was 1.773, 95% confidence interval (95%CI) 1.033 to 3.214, P=0.015].
Serum PCT evaluation may be helpful in differentiating sepsis and non-sepsis at early stage of disease, and also in predicting the severity of the illness and prognosis of SIRS. PCT may be one of the independent risk factors for 28-day survival.