Estimation of Glomerular Filtration Rate Using Serum Cystatin C as an Early Predictor of Renal Insufficiency in Overweight/ Obese Children and Adolescents with Non-alcoholic Fatty Liver Disease

Background: NAFLD is a clinical spectrum ranging from steatosis (fatty infiltration) to steatosis with inflammation, necrosis, fibrosis and cirrhosis resembling alcoholic hepatitis in the absence of alcoholic abuse. The aim of this work was to determine early renal functional alterations in overweight / obese children and adolescents with NAFLD, as assessed by estimated glomerular filtration rate using cystatin C, and to evaluate its relation to the degree and various clinic-laboratory parameters of NAFLD.

Methods: This case control research included 60 overweight and obese children and adolescent. The Cases were classified into two equal groups: group 1: overweight or obese children and adolescents with NAFLD and group 2: overweight or obese children and adolescents without NAFLD. Twenty healthy age-and-sex matched children with BMI less than the 85th percentile for age and sex were chosen as controls.

Results: There was significantly positive correlation among serum cystatin C and weight, BMI, Waist/Hip ratio, ALT, AST, cholesterol, Hip circumference, Fasting plasma insulin and Insulin resistance. There was significantly negative correlation among serum cystatin C and eGFR. There were significant negative correlations between eGFR and weight z score, BMI z score, hip circumference, waist/hip ratio, ALT, AST, cholesterol, fasting plasma insulin, insulin resistance and cystatin C.

Conclusions: Serum Cystatin C correlated significantly to the degree of hepatic steatosis. Values of eGFR were significantly lower in NAFLD patients compared to those without NAFLD and controls. The reduction in eGFR was correlated significantly with the degree of hepatic steatosis. There was a statistically significant negative correlation between serum cystatin C and eGFR. Levels of eGFR were significantly correlated with weight, BMI, W/H ratio, ALT, AST, cholesterol and insulin resistance.