ESPE Abstracts (2015) 84 P-3-831

Evaluation of Renal Functions in Obese Children and Adolescents with Cystatin-C and Creatinin Based GFR: is Increasing GFR Reflected Hyperfiltration and Possible Renal Damage in Future?

Dilsah Onerli Salman, Zeynep Siklar, Nisa Eda Cullas Ilarslan, Pinar Kocaay, Birsin Ozcakar & Merih Berberoglu

Faculty of Medicine, Ankara University. Ankara, Turkey

Introduction: There is a growing interest in the relationship between obesity and renal damage. Chronic kidney disease is accepted as an important complication of obesity in adulthood. However, information on association between childhood obesity and renal functions is limited. In this study, It is aimed to investigate the renal functions in obese children and adolescents.

Patients and methods: We enrolled 107 obese children and adolescents as a study group and 47 normal-weighted children as a control group. Serum cystatin-C, serum creatinin levels, 24 h proteinuria, creatinin clearance (CrCl) and glomerular filtration rate (GFR) were evaluated in groups. Estimated GFR was measured by both creatinin based (Schwartz, Counahan-Barratt) and cystatin–C based (Filler) formulas. Metabolic parameters (blood glucose, insulin, lipids) were analysed in obese subjects. IDF criterias was used to determine of metabolic syndrome (MetS).

Results: The mean age of obese patients was 12.57 years; and 15 of 95 obese children (>10 years of age) had MetS. Proteinuria and serum cystatin–C levels were not different between obese and control groups. Obese patients with MetS have higher Cystatin-C level than without MetS. CrCl, Filler, and Counahan-Barratt measurements showed statistically significant increase in GFR of obese subjects than control subjects (147 vs 117, 138.8±26.1 vs 118.06±26.6, 137.2±26.9 vs 122.9±27.7 respectively). These increase is negatively correlated with duration of obesity. Only Filler equation showed statistically significant decrease of eGFR in patients with metabolic syndrome.

Conclusions: In obese children and adolescents renal damage seems to be at functional level reflecting glomerular hyperfiltration without proteinuria. However, as obesity duration is incresed, eGRF is began to decrease, possibly beginning with nephropathy. Although serum cystatin-C levels can be useful for prediction of nephropathy only in obese children with MetS, GFR measurement is advantageous for detecting unfavourable effect of childhood obesity on renal functions either with or without MetS.