A-339 Comparison of eGFR Calculated by CkiD Bedside Equation and CkiD U25 Equation in Pediatric Patients

Background Glomerular filtration rate (GFR) estimation is crucial for assessing kidney function in pediatric patients. Unlike adults, children exhibit varying kidney function that changes with age, size, and puberty. To implement the age- and sex-specific Chronic Kidney Disease in Children (CkiD) U25 equation for pediatric patient GFR estimation in our institution, we compared the eGFR results generated by our currently used CkiD Schwartz bedside equation, which relies on height and serum creatinine, with the results calculated by U25 equation. The aim of this study is to evaluate the difference between the two equations and to investigate the clinical implications of the difference. Methods We analyzed 260 pediatric patients (104 female, 156 male) aged 1 to 17 years with mild to moderate CKD (eGFR<90 ml/min/1.73m^2). Patients were categorized according to age, sex and races. EP Evaluator EE12 was used to analyze the eGFR calculated by the two equations. Results Compared to the bedside equation, the U25 equation showed a bias of -7.8 (-10.6%) and correlation coefficient (R) of 0.9757 in females, and a bias of 4.8 (6.3%) and R of 0.8534 in males. In males aged 1 to 13, the U25 equation had a negative bias of -4.3 (-5.7 %) and R of 0.9721; in males aged 14 to 17, it had a positive bias of 10.1 (13.1 %) and R of 0.9814. The bias was unrelated to race but dependent on age, decreasing with age in females and increasing in males. For females, 56 out of 104 (53.8%) U25 eGFR were within 10% (P10) of bedside eGFR, and all were within P30. Regarding to the GFR stages, only 3 females from G2 (GFR 60-89) were reclassified to G3a (GFR 45-59). In males aged 1 to 13, 52 out of 57 (91.2%) were within P10, and all were within P30. However, in males aged 14 to 17, only 20 out of 99 (20.2%) were within P10, and all were within P30. Reclassifications included 9 males from G3a to G2, 1 from G2 to G3a, and 33 from G2 to G1 (GFR>90). Conclusion The CkiD U25 eGFR showed age- and sex-dependent bias compared to the CkiD Schwartz bedside equation. In the majority of females and males aged 1 to 13 years, the negative bias did not lead to a reclassification of GFR stages. However, about half of the males aged 14 to 17 were reclassified to less severe GFR stages. Therefore, clinicians should be aware of this change and its potential impact on patient management.