Diagnostic value of cystatin c urine level as an early marker of diabetic nephropathy in children with type 1 diabetes mellitus

Aim. To improve the diagnosis of early stages of diabetic nephropathy by examining cystatin C urine excretion in children with type 1 diabetes mellitus. Methods. 83 children aged 11 to 18 years with type 1 diabetes mellitus were included in the study. Children were divided into 3 groups according to the duration of diabetes mellitus: group 1 - 1 to 2 years (n=18), group 2 - 2 to 5 years (n=24), group 3 - over 5 years (n=41). Results. The average values of glycated hemoglobin did not differ significantly between the groups and were assessed as following: group 1 - 8.61±2.1%, group 2 - 8.91±1.5%, group 3 - 8.84±2.5% (p >0,05). Development of «symptomatic» diabetic nephropathy occurred in 10% of children with type 1 diabetes with disease duration over 5 years. Cystatin C urine excretion was the highest in children with long clinical course of type 1 diabetes mellitus (p <0.01). Significant variability of cystatin C urine excretion was observed even in children with diabetes duration of 1 to 2 years. Pairwise comparison of cystatin C urine excretion levels and glycated hemoglobin values of children with type 1 diabetes did not show any statistically significant difference. Conclusion. Cystatin C urine excretion level can be an early marker of kidney damage and depict the state of tubular renal function in children with type 1 diabetes mellitus. Tubular dysfunction in children with type 1 diabetes mellitus might be diagnosed when observed cystatin C urine excretion level is over 21.9±1.4 ng/ml (sensitivity 70%, specificity 60%).

children, diabetic nephropathy, diabetes mellitus, cystatin C