The value of N-terminal pro-brain natriuretic peptide combined with neonatal critical illness scores on mortality risk evaluation in very low birth weight infants

Objective To explore the value of plasma N-terminal pro-brain natriuretic peptide(NT-proBNP) level combined with the Neonatal critical illness scores(NCIS) on mortality risk evaluation in very low birth weight infants(VLBWI). Methods Between Jun.2011 and Dec.2012, preterm infants admitted to the Neonatal Intensive Care Unit of the First Affiliated Hospital of Zhengzhou University within 6 hours after birth, with birth weight <1500 g were eligible.All the infants were scored with the use of NCIS, and plasma NT-proBNP levels were measured simultaneously.A Logistic regression analysis(Method=Enter) was performed to determine the independent risk factors.The value of relevant factors on mortality risk evaluation were determined and compared with the use of receiver operator characteristic(ROC) curve.The extent to which NT-proBNP reassigned individuals to risk categories that better predicted the mortality risk was assessed by use of the net reclassification index(NRI) measure. Results One hundred and twenty-two cases of VLBWI(male/female=64/58 cases) were included in the study.The total mortality rate was 17.21%(21/122 cases). The NT-proBNP, NCIS score, pH, pa(O2), blood urea nitrogen(BUN), hematocrit(HCT), systolic blood pressure, occurrence of gastrointestinal injury and occurrence of intubation among those neonates who died was significantly different with those who didn't(all P 19 580 ng/L, the sensitivity was 95.21%, the specificity was 87.13%.The area under the ROC curve for NCIS was 0.816, with the cut-off ≤ 76, the sensitivity was 95.19%, the specificity was 56.41%.The area under the ROC curve for NT-proBNP along with NCIS was 0.947, the sensitivity was 100.00%, the specificity was 84.18%.The addition of NT-proBNP to NCIS in prediction of mortality risk significantly improved the net reclassification improvement(NRI=0.385, Z=2.714, P=0.034). Conclusions The addition of NT-proBNP to NCIS significantly improve the predictive value on mortality risk, predicting the mortality risk early and accurately. Key words: Very low birth weight infants; N-terminal pro-brain natriuretic peptide; Neonatal critical illness scores; Prediction; Mortality risk