Serum cystatin C predicts acute kidney injury in preterm neonates with respiratory distress syndrome

We aimed to compare serum cystatin C levels (sCysC) in preterm neonates with respiratory distress syndrome (RDS) with a control group and to investigate whether it could be used as a predictor for acute kidney injury (AKI). sCysC was measured in 62 neonates with RDS (n = 28) and control neonates without RDS (n = 34), whose gestational ages (GA) were between 27 and 29 weeks (subgroup 1) and 30-32 weeks (subgroup 2). AKI was defined as oliguria and/or increase of serum creatinine. Blood samples were obtained on postnatal days (PND) 3 and 30. sCysC levels were determined by particle-enhanced nephelometric immunoassay. There were six neonates with AKI (RDS-AKI subgroup) and 22 neonates without AKI (RDS-no AKI subgroup) during the first 7 days. Although sCysC levels were lower in neonates with RDS than controls on PND3 in both GA subgroups, the differences were not significant. However, in neonates with RDS and AKI, sCysC levels were significantly higher than neonates with RDS but no AKI and neonates in the control group on PND3. sCysC level was found to have a statistically significant association with AKI development in preterm neonates with RDS. sCysC is an independent predictor of AKI in preterm neonates with RDS.