Predictive value of urinary cystatin C for mortality in critically ill neonates

Abstract

Objective To determine if urinary cystatin C (uCys C) level can predict mortality in critically ill neonates. Methods This prospective study included neonates admitted to the intensive care unit within the first 6 hours of life from May.2011 to Oct.2012.Neonates were assigned into survivor and non-survivor groups based on whether they died during the first week of life.The uCys C level was measured on the day of admission.The score for neonatal acute physiology (SNAP) was calculated based on 28 items collected during the first 24 hours of admission.Multivariate Logistic regression analysis was used to determine whether uCys C level was a predictor of mortality.A receiver operating characteristic (ROC) curve was constructed and the area under the ROC curve (AUC) was calculated to assess the predictive strength. Results Of the total 155 neonates, 12 cases (7.1%) died during the first week of life.When compared to survivors, the gestational age (t=2.810, P=0.006) and birth weight (t=3.245, P=0.001) in non-survivors were significantly lower; but the uCys C level (z=-3.426, P=0.001), the SNAP score (z=-3.308, P=0.001), and the use of mechanical ventilation (χ2=23.877, P=0.000) were significantly higher.Logistic regression analysis revealed that uCys C remained significantly associated with mortality after adjusting for gestation age, birth weight, or the SNAP score (P=0.024). uCys C achieved AUC of 0.81 (95% CI: 0.71-0.92, P=0.001). When combined with SNAP and mechanical ventilation, the predictive performance of uCys C improved AUC 0.93 (95% CI: 0.86-1.00, P=0.000). Conclusion uCys C is significantly associated with adverse outcome of death and independently predictive of mortality in critically ill neonates. Key words: Critically ill neonates; Mortality; Urinary cystatin C; Predictive value