Assessment of Kidney Function Discrepancies in Pediatric CAKUT Patients Using Bedside Schwartz Equation and Renal Scintigraphy

Abstract

Background and Objectives: This research explores the correlation between estimated glomerular filtration rates (eGFR) obtained using the bedside Schwartz equation, and renal scintigraphy in children with congenital kidney and urinary tract abnormalities (CAKUT). The objective is to enhance understanding and management of renal health in this demographic by analyzing kidney size-function relationships. Methods: A retrospective observational analysis was performed on 94 pediatric CAKUT patients at the “Louis Turcanu” Emergency Hospital for Children, Timisoara. Kidney function data, extracted from medical records, were evaluated using the Schwartz equation, renal scintigraphy, and the gold standard iohexol clearance. Ethical approval was secured for the study, which employed descriptive and inferential statistical methods, including t-tests and correlation coefficients, to compare eGFR values. Results: Significant variances were found in eGFRs across different body surface area (BSA) percentiles. For instance, the eGFR for the right kidney in the 25th–50th BSA percentile (102.02 ± 41.52 mL/min/BSA) was notably higher than that of the left (35.60 ± 26.05 mL/min/BSA; p = 0.01). The overall sample reflected a higher eGFR in the right kidney (76.03 ± 40.91 mL/min/BSA) compared to the left (57.46 ± 35.91 mL/min/BSA; p = 0.02). Additionally, a strong positive Pearson correlation (r = 0.80, p = 0.02) was found between scintigraphy and ultrasound measures in the 50th–75th percentiles for left renal percentiles, demonstrating consistent patterns across different evaluations of kidney function. Conclusions: This comparison indicates a complex relationship between eGFR values and kidney size, suggesting potential inaccuracies in standard bedside eGFR measurements for pediatric CAKUT patients. The findings underscore the necessity for accurate diagnostic tools specifically designed for pediatric applications and advocate for the integration of multiple diagnostic techniques to improve clinical management.

Keywords

• pediatric nephrology
• chronic kidney disease
• kidney imaging
• kidney function assessment
• renal scintigraphy