The Glomerular Filtration Rate and Proteinuria in Obese Children

Obesity increases the risk of many pathologies, including cardiovascular and renal diseases. This study aimed to determine the association between obesity and proteinuria as well as glomerular hemodynamic changes (an early marker of kidney damage) in obese children and its relationship with metabolic syndrome.

This case-control study included 112 overweight and obese male and female patients aged 7 - 16 years, and 35 age- and gender-matched healthy controls. The obese patients were divided into 4 subgroups according to BMI:normal weight (control group), overweight, obese, morbidly obese. The glomerular filtration rate was estimated using classical and adjusted formulas based on the various body size descriptors of Leger, Schwartz, Filler, and Zappitelli, and chronic kidney disease formulas in all patients and controls. Creatinine, cystatin C, 24-hour urine protein, and the estimated glomerular filtration were compared between groups.

Blood pressure, creatinine, and 24-hour urine protein values were significantly higher in the overweight and obese patient subgroups (P < 0.05). The estimated glomerular filtration rate, which was calculated using creatinine or cystatin C, was higher in the obese patients and subgroups than in the control group (P < 0.05). In contrast, the estimated glomerular filtration rate measured using both classical and adjusted formulas was significantly lower in the obese patients than in the controls (P < 0.05).

Early indicators of renal damage are elevated urine protein and renal function test results compatible with impaired renal function. As such, obese pediatric patients should be routinely monitored for blood pressure, renal function, and proteinuria