COMPARATIVE EVALUATION OF METHODS FOR DETERMINATION OF GLOMERULAR FILTRATION RATE IN CHILDREN WITH TYPE 1 DIABETES MELLITUS

Aim. To compare the methods for estimating glomerular filtration rate (GFR) in children with type 1 diabetes mellitus (DM) by means of determining blood serum creatinine and cystatin C concentrations so as to optimize early detection of diabetic kidney disease. Materials and methods. Thirty four DM1 patients (18 girls and 16 boys aged 8-18) with disease duration for more than 2 years were examined. GFR was assessed by creatinine level using Schwarz formula and serum cystatin C level – by means of special tables. Results. Reliable dependence of mean serum cystatin C concentration on DM «history» was found. In children with disease lasting for more than 5 years, cystatin C level was significantly higher than in patients with DM duration for less than 5 years: 1,05±0,28 mg/l versus 0,70 ±0,21 mg/l ( p =0,001). No statistically significant differences regarding creatinine indices (59,8±18,1 mmol/l and 52,3±15,4 mmol/l, respectively) were obtained. GFR calculated by cystatin C in the group of children suffering from DM for more than 5 years was 80,3±33,5 ml/min and was significantly lower than in children with disease «history» less than 5 years (123,8±44,5 ml/min; p =0,001). Correlation dependence between cystatin C level, GFR calculated by cystatin C, disease duration and age of DM debut was established. Conclusion. Early changes in GFR in children with diabetic lesion of kidneys can be diagnosed by means of cystatin C. According to our data, serum cystatin C is a more exact GFR marker than serum creatinine.