Ultrasonographically determined kidney volume and progression to end-stage kidney disease in pediatric chronic kidney disease: data from the KNOW-Ped CKD study

Abstract Background We investigated the relationship between ultrasonographically determined renal volume relative to body surface area (BSA) and estimated glomerular filtration rate (eGFR) and determined whether chronic kidney disease (CKD) progression outcomes could be predicted based on each kidney volume ratio in pediatric patients with CKD. Methods From the KNOW–ped CKD cohort, 304 patients who underwent renal ultrasonography (US) were investigated for the kidney’s length and depth in the longitudinal axis and the width in the transverse plane passing through the hilum’s center. The formula, 0.523×length×depth×width, was used to calculate each kidney volume. The total kidney volume (TKV) was the sum of the volumes of each kidney and was adjusted for BSA. Each kidney volume ratio was calculated as the ratio of the smaller to the large kidney volume. Results Scatter plot and linear regression analysis revealed the relationship between eGFR and BSA–adjusted TKV, and this linear relationship differed significantly based on the percentile ratio of each kidney volume. Q2 quartile of each kidney volume ratio had a significantly lower risk in CAKUT, while Q1 had higher risk of requiring renal replacement therapy compared to single kidney in GN. Conclusion The relationship between eGFR and BSA–adjusted TKV in pediatric patients with CKD differed based on CKD’s primary etiology and the asymmetry derived from each kidney volume ratio. This asymmetric renal morphological change based on each renal volume ratio is clinically reflected in predicting the prognosis of CKD progression in children. Trial registration number and date of registration: NCT number NCT02165878 on June 11, 2014.