[Predictive value of plasma cell-free DNA for prognosis of sepsis]

To explore the predictive value of plasma cell-free DNA (cf-DNA) for prognosis in patients with sepsis.

105 patients with sepsis admitted to department of emergency of the First Hospital of Quanzhou Affiliated to Fujian Medical University from June 2015 to June 2017 were enrolled. Patients were divided into sepsis group (n = 50) and severe sepsis group (n = 55). At the same time, 50 cases of physical examination center in our hospital were randomly selected as the healthy control group. The differences of cf-DNA, procalcitonin (PCT) and acute physiology and chronic health evaluation II (APACHE II) score among the three groups were compared. The correlation between cf-DNA and PCT or APACHE II were analyzed by Bivarite method. Logistic regression was used to analyze the independent predictors of sepsis. The receiver operating characteristic curve (ROC) was made to evaluate cf-DNA, PCT, APACHE II alone or combined ability to predict the prognosis of sepsis.

The PCT, APACHE II and cf-DNA in the sepsis group and severe sepsis group were significantly higher than those in the healthy control group [PCT (μg/L): 5.80 (3.28, 8.85), 17.53 (8.40, 29.61) vs. 0.02 (0.01, 0.03); APACHE II: 13.04±3.03, 23.29±8.02 vs. 2.10±1.05; cf-DNA (μg/L): 1 438.0 (1 154.0, 1 576.0), 2 595.0 (2 162.0, 5 198.0) vs. 17.0 (13.0, 20.5); all P < 0.05], and the indicators in the severe sepsis group were further higher than the sepsis group (all P < 0.05). Correlation analysis showed that cf-DNA was significantly positive correlated with PCT [r = 0.675, 95% confidence interval (95%CI) = 0.575-0.766, P < 0.001] and APACHE II (r = 0.911, 95%CI = 0.874-0.939, P < 0.001). ROC curve analysis showed that the areas under ROC curve (AUC) of PCT, APACHE II, cf-DNA, PCT+APACHE II, cf-DNA+PCT, cf-DNA+APACHE II, cf-DNA+PCT+APACHE II to predict the prognosis of sepsis patients were 0.898, 0.905, 0.961, 0.941, 0.974, 0.976 and 0.982, respectively. It was shown that when predicted alone with PCT, APACHE II and cf-DNA, the AUC of cf-DNA was the largest (0.961), the sensitivity was 100%, and the specificity was 81.43%; the combined prediction of cf-DNA with PCT or APACHE II could further increase AUC, and the combined prediction of cf-DNA, PCT and APACHE II had the highest AUC (0.982), the sensitivity was 94.29%, the specificity was 98.57%.

cf-DNA, PCT and APACHE II have certain predictive value for the prognosis of sepsis. The value of cf-DNA was the highest when predicted alone, but the predictive ability of cf-DNA combined with PCT and APACHE II was the best.