Comparison of various prediction equations for glomerular filtration rate in Korean pediatric cancer patients: a retrospective study

Purpose: Assessment of kidney function is essential in the management and follow-up of children with cancer. However, the best method to assess the kidney function in children with cancer is unknown.Methods: The study compared glomerular filtration rate (GFR) using various methods. Four methods for determining GFR are as follows: technetium-99m diethylenetriaminepentaacetic acid clearance (mGFR), serum creatinine (sCr)-based equations (eGFR- Schwartz and eGFR-Pottel), cystatin C (CysC)-based equations (eGFR-Zappitelli1 and eGFR-CKiD1), and combined sCr-CysCbased equations (eGFR-Zappitelli2 and eGFR-CKiD2).Results: A total of 54 pediatric patients diagnosed with cancer were evaluated. The estimated GFR (eGFR) equations showed moderately correlated with mGFR, with eGFR-Zappitelli2 showing the highest correlation (r=0.639, P<0.001). The GFR-Schwartz and eGFR-Pottel equations had mean biases of –5.72 mL/min/1.73 m2 and –6.64 mL/min/1.73 m2, with 20.4% and 57.4% of values within 10% and 30% of mGFR for GFR-Schwartz, and 20.4% and 48.1% for eGFR-Pottel, respectively. The CysC-based eGFR showed significant bias with mean bias of –30.9 mL/min/1.73 m2 for eGFR-Zappitelli1 and –53.8 mL/min/1.73 m2 for eGFR-CKiD1. The combined sCr-CysC-based equations of eGFR-Zappitelli2 had a mean bias of –1.32 mL/min/1.73 m2, with 16.7% of values within 10% accuracy and 57.4% within 30% accuracy. The eGFR-CKiD2 had a mean bias of –34.7 mL/min/1.73 m2 and the best accuracy, with 27.8% and 59.3% of values falling within 10% and 30%, respectively.Conclusions: Among the methods evaluated, the combined sCr-CysC-based eGFR showed better accuracy with mGFR compared with the other equations in children with cancer.