Measurement and Estimation of Glomerular Filtration Rate in Children With Neurogenic Bladder: A Prospective Study

Abstract

ObjectiveTo evaluate the performance of different equations used to estimate glomerular filtration rate (GFR) in children with neurogenic bladder (NB). MethodsThe GFR measured with the technetium-99m-diethylenetriaminepentaacetic acid (99mTc-DTPA) dual-plasma sample clearance method was defined as the true GFR (tGFR). The Chronic Kidney Disease in Children (CKiD) equation for serum creatinine (Scr) and/or cystatin C (Cys C) was used for GFR calculation. Estimated GFR (eGFR) using CKiDScr, CKiDCys C, and CKiDScr+Cys C equations was compared with tGFR in children with NB. ResultsIn total, 458 children with NB were prospectively enrolled in this study. The mean tGFR was 73.84 ± 18.54 ml/min/1.73 m2, mean eGFRScr was 77.94 ± 18.38 ml/min/1.73 m2, mean eGFRCys C was 74.20 ± 17.64 ml/min/1.73 m2, and mean eGFRScr+Cys C was 75.70 ± 18.07 ml/min/1.73 m2. The correlation between the Scr-based equation and 99mTc-DTPA clearance method was low (r = 0.648). The Cys C-based equations exhibited the strongest correlations: CKiDCys C (r=0.891) and CKiDScr+Cys C (r = 0.879). The overall prevalence of chronic kidney disease (CKD) was 20.7%, 19.7%, 17.5%, and 12.4% according to tGFR, eGFRCys C, eGFRCys C+Scr and eGFRScr, respectively. The area under the curve (AUC) for the Receiver operating characteristic (ROC) curve of the CKiDCys C equation was the highest (AUCCKiDcys = 0.956). ConclusionThe Cys C-based CKiD equation was the most accurate for estimating GFR compared with 99mTc-DTPA clearance method in children with NB. The CKiDScr equation overestimated the GFR. The CKiDCys C equation can be used to detect initial stages of CKD in children with NB.