Presented at the Neonatal Society 2017 Spring Meeting.
Yuliya H, Anastasiya B, Ludmila A
Bukovinian State Medical University, Department of Pediatrics, Neonatology and Perinatal Medicine
Background: Serum cystatin C (SCysC) is a proteinase inhibitor involved in intracellular catabolism of proteins, produced by all nucleated cells, freely filtrated across glomeruli, and completely catabolized and reabsorbed in the proximal tubule. Several authors found that SCysC is a better marker of neonatal acute kidney injury (AKI) than creatinine but there are limited studies available on reference values of SCysC in healthy and ill neonates (1-4). The objective of the work was to determine diagnostic and predictive value of SCysC in case of acute kidney injury (AKI) in critically ill full-term newborns.
Methods: A comprehensive paraclinical examination of 67 critically ill full-term newborns including 36 infants without AKI (I group), and 31 ones with diagnosed AKI (II group). AKI was detected by means of recommendations Kidney Disease: Improving Global Outcomes with modification by J. G. Jetton & D. J. Askenazi (5). The level of SCysC was measured by immunonephelometric methods on the basis of the laboratory Gemeinschaftslabor Cottbus (Germany). The results of each group are expressed as mean and 95% confidence interval (95% CI). Where data were available, 2×2 tables were constructed to derive sensitivity, specificity, positive predictive value (PPV), negative predictive value (NPV), positive likelihood ratio (PLR), and negative likelihood ratio (NLR) and cut-off level of SCysC. Area under the receiver operating characteristic (ROC) curves (AUROCs) was used to deduce the diagnostic accuracies of the SCysC. Ethical approval was obtained from the research ethics committee of the Bukovinian State Medical University.
Results: The newborns of the first group of level of SCysC was 1.56 mg/l (1.517-1.62), in the second group – 1.78 mg/l (1.73-1.82), p<0,05. A high sensitivity (100.0 (88.8-100.0)%) of SCysC has been found during diagnostics of AKI in critically ill full-term newborns. High diagnostic value of this index is proved by diagnostic accuracy (82.1%) and high AUROC index (0.86, p<0,05); high predictive value – by high readings of a PPV (70.5 (60.7-78.6)%) and NPV (100.0%), and also PLR (2.8 (1.8-4.3)). A cut-off level of SCysC which is indicative of the formation of AKI in full-term newborns with severe perinatal pathology was detected to be higher than 1.59 mg/l.
Conclusion: Considering a high predictive and diagnostic value the authors recommend to measure SCysC level for identification of AKI in full-term infant into the practical work of neonatal intensive care units.
Corresponding author: Langust76@mail.ru
1. Gopal G. (2014) Acute Kidney Injury (AKI) in perinatal asphyxia. Indian J. Pharm. Biol. Res., 2(2), 60-65.
2. Ottonello G., Dessì A., Neroni P., Trudu M. E., Manus D., Fanos V. (2014) Acute kidney injury in neonatal age. Journal of Pediatric and Neonatal Individualized Medicine, 3(2), e030246 doi: 10.7363/030246.
3. de Albuquerque Cavalcanti Ferreira Novo A.C., dos Santos Rodrigues Sadeck L., Suely Okay T., Rodrigues Leone C. (2011) Longitudinal study of Cystatin C in healthy term newborns. Clinics, 66, 217-20.
4. Grubb А., Nyman U., Björk J., Lindström V., Rippe B., Sterner G., Christensson A. (2005) Simple cystatin C-based prediction equations for glomerular filtration rate compared with the modification of diet in renal disease prediction equation for adults and the Schwartz and the Counahan-Barratt prediction equations for children. Clin. Chem., 51(8), 1420-1431.
5. Selewski D.T., Charlton J.R., Jetton J.G. (2015) Neonatal Acute Kidney Injury. Pediatrics, 136 (3), Е463-473.