Serum cystatin C as an early predictor of acute kidney injury in preterm neonates with respiratory distress syndrome.

Preterm neonates with respiratory distress syndrome (RDS) are at increased risk of acute kidney injury (AKI). Our study aimed at determining whether serum cystatin C (sCysC) on day 3 of life (D3) can early predict AKI in preterm neonates with RDS. This prospective study was conducted on 75 preterm neonates; 50 with RDS and 25 without RDS. On D3, sCysC, serum creatinine (sCr) and blood urea nitrogen (BUN) were measured and estimated glomerular filtration rate (eGFR) was calculated. sCr and BUN levels were measured again on days 5 and 7. Neonates were evaluated for development of AKI during first week of life according to the modified pediatric RIFLE (pRIFLE) criteria. Thirteen neonates with RDS developed AKI (26%).There was no significant difference between RDS and control groups with respect to sCysC. RDS neonates with AKI had significantly higher sCysC than those without AKI (1.62 ± 0.12 versus 1.16 ± 0.09 mg/l; p < .001). RDS grade III-IV neonates had significantly higher sCysC than RDS grade I-II. There was a significant positive correlation between D3 sCysC and (D5 and D7 sCr and BUN). Receiver operating characteristic (ROC) curve showed that D3 sCysC can predict AKI in preterm neonates with RDS at a cutoff point of >1.3 mg/l with sensitivity of 92.30% and specificity of 96%. We conclude that neonates with RDS are at increased risk of AKI. sCysC on day 3 of life can predict AKI earlier than Cr and eGFR.