Evaluation of the levels of kidney injury molecule-1 and cystatin C as early biomarkers for prediction of acute kidney injury complications in paediatric male patients – a case-control study

Introduction:
Acute kidney injury (AKI) is a serious problem in children and adolescents because it is associated with higher morbidity and mortality, and it may progress rapidly and lead to chronic renal disease, which would require dialysis. Kidney injury molecule-1 (KIM-1) and serum cystatin C are recognised as early sensitive and specific biomarkers for kidney injury. The study aims to predict KIM-1, cystatin C, and other kidney function biomarkers in AKI paediatric patients.

Material and methods:
A total of 120 paediatric males were used in the present study divided into 90 patients with AKI with a mean age of 5.94 ±4.93 years. All patients were divided according to RIFLE (renal, injury, failure loss, end- stage) for 3 stages: stage 1 (32 patients); stage 2 (27 patients); and stage 3 (31 patients), and controls (30) with a mean age of 7.70 ±5.02 years. The data were collected for this research at the Kidney Unit in Kerbala Teaching Hospital, Kerbala, Iraq.

Results:
The study found that KIM-1 significantly (p ≤ 0.001) increased in all stages of AKI patients: stage 1 (1501.64 ±417.02); stage 2 (1638.91 ±354.85); stage 3 (1474.16 ±425.63), and the controls (716.64 ±50.72); moreover, highly significant differences (p ≤ 0.001) in cystatin C in all stages of AKI patients: stage 1 (12.52 ±3.02); stage 2 (13.23 ±2.42); stage 3 (11.85 ±3.04); and the controls (5.32 ±1.71). The glomerular filtration rate (GFR) by s Cr/cystatin C ratio was significantly (p ≤ 0.001) decreased in all stages. The highest decrease of GFR was calculated for cystatin C for all stages compared to the control and highly significant differences (p ≤ 0.001) in elevated levels of kidney function tests (serum creatinine, serum urea, C-reactive protein – CRP, chloride – Cl, potassium – K, and blood urea nitrogen – BUN) in AKI and highly significant differences (p ≤ 0.001) in the decrease of GFR, albumin, and urine output.

Conclusions:
Finally, higher serum KIM-1, serum cystatin C, serum creatinine, serum urea, CRP, Cl, K, and BUN, while decreasing each of the GFR, albumin, and urine output in AKI patients, are related to early prediction of renal complications. Therefore, KIM-1 and cystatin C can be considered as biomarkers for AKI.