Cystatin C as a biomarker of acute kidney injury in a group of critically ill children in a pediatric intensive care unit

Introduction: Acute kidney injury (AKI) is known to be one of the major complications of critically ill children and accounts for a 30%-90% mortality of such patients. Early identification of such patients can significantly influence their mortality and morbidity. Objectives: Serum creatinine levels are not a good marker of early renal dysfunction. Numerous novel biomarkers have been proposed for the detection of AKI. In this study we sought to evaluate the ability of serum creatinine and serum cystatin C levels in the early detection of AKI. Patients and Methods: In this prospective study, serum cystatin C and creatinine levels were serially measured in a group of critically ill children older than 6 months, admitted to the intensive care unit of a tertiary care children hospital. Results: Around 54 patients were evaluated in this study. About 13 of them developed AKI. Serum cystatin C levels significantly changed over time in these patients. Changes in cystatin C levels were more prominent in patients with AKI in comparison with patients with normal renal function or those at risk for kidney injury. Rate of serum cystatin C elevation was more rapid than serum creatinine elevation in patients with AKI (p<0.05) and thus serum cystatin C levels can detect kidney injury earlier. Conclusion: Serum cystatin C is applicable as a good biomarker of renal function in early stages of kidney injury. Hence, we can use serum cystatin C for the early detection of AKI in patients more accurately.