Comparison of methods to estimate glomerular filtration rate in paediatric oncology patients

Area of Science:

• Pediatric Nephrology
• Oncology
• Clinical Chemistry

Background:

• Glomerular filtration rate (GFR) estimation is vital for pediatric oncology patients.
• Limited evaluation exists for GFR equations, especially those not relying on serum creatinine, in this specific demographic.
• Accurate GFR assessment is critical for drug dosing and monitoring renal function in children undergoing cancer treatment.

Purpose of the Study:

• To compare the predictive performance of various equations for estimating GFR in pediatric oncology patients.
• To identify the most accurate and precise GFR estimation methods for this vulnerable population.
• To evaluate equations that do not require serum creatinine levels.

Main Methods:

• Measured GFR (mGFR) was determined using a chromium 51-labeled ethylene diamine tetraacetic acid excretion test.
• Estimated GFR (eGFR) was calculated using 22 different equations from existing literature.
• Comparative analysis of mGFR and eGFR values, assessing bias, precision, and accuracy of each equation.

Main Results:

• 124 mGFR values from 73 children were analyzed, with a range of 7 to 146 mL/min.
• The Flanders metadata equation demonstrated the lowest absolute bias (0.9 mL/min) and highest precision (RMSE 13.1 mL/min).
• The univariate Schwartz equation achieved the highest percentage of eGFR values within 30% of mGFR (81.5%), while the Rhodin fat-free mass equation had the highest percentage within 10% (37.1%).

Conclusions:

• Several equations can estimate renal function in pediatric oncology patients, but none achieved high accuracy.
• The Flanders metadata and univariate Schwartz equations performed best in this study.
• These two equations are suggested for cautious use in clinical decision-making for pediatric oncology patients, acknowledging their inherent limitations.