Serum cystatin C and urinary neutrophil gelatinase-associated lipocalin in pediatric acute kidney injury; a cross-sectional study

Background: Acute kidney injury (AKI) refers to insults that lead to decreased kidney function within hours to weeks and can be associated with complications including chronic kidney failure, end-stage renal disease and even death. Although various biomarkers have been proposed to predict AKI in children, but no consensus has been reached on the best diagnostic method. Accordingly, the present study aimed to assess the correlation between urine NGAL levels and development of AKI in children and determine which one of the biomarkers of urine NGAL, serum Cystatin C and serum creatinine has a stronger association with AKI in the pediatric population.Methods: The present cross-sectional study was conducted on children younger than ۱۴ years of age, hospitalized in the intensive care unit of Children’s Medical Centre in Tehran, Iran, during ۲۰۱۶. Urine NGAL, serum Cystatin C and serum creatinine levels of these subjects were measured on admission to the intensive care unit. The concentrations of serum Cystatin C and serum creatinine were measured again after ۴۸ hours to determine the AKI status of the subjects. Data were analyzed to determine the association between GFR and the concentrations of evaluated biomarkers and to compare the levels of biomarkers between the four groups of no AKI, injury, failure, loss and end-stage.Results: A total of ۱۰۴ children (۵۹ boys and ۴۵ girls, average age=۲۸.۰±۳.۵ months) were included in this study. The mean level of uNGAL on admission in the No-AKI group (۱۵۳.۷۹±۲۹.۸۲) was significantly lower than the children in the injury (۱۲۲۵.۰ ±۲۷۵.۰) and failure (۷۵۶.۵۶±۱۴۷.۷۹) groups (df:۳, ۱۰۰; F=۱۰.۷۴; p<۰.۰۰۰۱). The mean concentration of Cystatin C on admission in the three groups of risk (۰.۹۴±۰.۳۰), injury (۱.۷۵±۰.۰۵) and failure (۱.۷۵±۰.۳۶) was also significantly higher than the No-AKI (۰.۲۷±۰.۰۴) (df:۳, ۱۰۰; F=۱۹.۲۱; p<۰.۰۰۰۱). However, there was no significant correlation between the level of serum creatinine on admission with pRIFLE classification (df:۳, ۱۰۰; F=۱.۲۵; p=۰.۰۹).Conclusion: Base on the findings of this study, it seems that compared to serum creatinine level, the concentrations of NGAL in urine and Cystatin C in the serum have stronger associations with the kidney function, with the latter providing a slightly higher prognostic value.