1. ESTIMATION OF eGFR IN CHILDREN WITH NORMAL OR SLIGHTLY IMPAIRED RENAL FUNCTION- COMPARISON OF THREE FORMULAS Katarzyna Jobs, Anna Jung, Marianna Lichosik, Małgorzata Placzyńska Pediatric Nephrology Department, Wojskowy Instytut Medyczny, Warsaw, Poland Assessment of glomerular filtration rate (GFR) is one of the basic needs in nephrology. The measurment of GFR with isotopic method is considered to be a golden standard. Unfortunately it has significant limitations (i.e. high cost, low availability for ambulatory practice). In clinical practice we often use so- called estimated filtration rate (eGFR). It is calculated from serum creatinine level with the use of few formulas- different for adults and children. In pediatrics Schwartz formula is the most popular. However it lacks precision in children with normal or slightly impaired renal function. Lately few new formulas were published, among them quadratic model by Gao and height- independent model by Pottel. AIM OF THE STUDY Aim of the study was comparison of three eGFR formulas (by Schwartz, Gao and Pottel) with GFR calculated with the use of isotopic method in children with slightly impaired (GFR>60ml/min/1,73m 2 ) or normal renal function (GFR >90 ml/min/1,73m 2 ). MATERIAL AND METHODS 59 patients (38 girls, 21 boys) aged 4-14 years (mean 8,2) with various urinary tract abnormalities- 49 with isotopic GFR >90 ml/min/1,73m 2 and 10 with isotopic GFR >60 ml/min/1,73m 2 (99mTc-DTPA) Statistical analysis: StatSoft, Inc.(2011). STATISTICA (data analysis software system, version 10 (www.statsoft.com). T-Student test; p ≤ 0,05. To calculate eGFR by Gao calculator from www.chuv.ch/quadraticformula was used. eGFR by Pottel was estimated with formula GFR 9ml/min/1,73m 2 = 107,3/[plasma creatinine level (mg/dl)/Q] with Q as linear function of age to be found in Pottel publication. Modification of Schwartz formula: eGFR = 0,413 x hight (cm)/plasma creatinine level (mg/dl) was used.www.chuv.ch/quadraticformula Schwartz formula: eGFR (ml/min/1,73 m 2 ) = k x height (cm)/creatinine (mg/dl) k = 0,413 2009 modification for all age groups Gao formula For boys: GFR (ml/min/1,73 m 2 ) = 0,68 x [height(cm)/creatinine(mg/dl)] – 0,0008 x [height(cm)/creatinine(mg/dl)] 2 + 0,48 x age (years) – 21,53 For girls: GFR (ml/min/1,73 m 2 ) = 0,68 x [height(cm)/creatinine(mg/dl)] – 0,0008 x [height(cm)/creatinine(mg/dl)] 2 + 0,48 x age (years) – 25,68 http://www.chuv.ch/quadraticformula Pottel formula. GFR (ml/min/1,73 m 2 ) = 107,3 / [creatinine(mg/dl)/Q] RESULTS eGFR by Gao formula do not significantly differ from isotopic GFR (p=0,12). Whereas eGFR by Schwartz formula and by Pottel formula significantly differ from isotopic GFR (p < 0,05) (Table 4). Formulas by Schwartz, Gao and Pottel were then compared with each other (Table 5). eGFR by Schwartz and Gao formula were significantly diffrernt, the same eGFR by Schwartz and Pottel. eGFR by Gao and Pottel differed nonsignificantly (p=0,225) (Table 5). Table 4. Comparison of isotopic GFR and eGFR by Schwartz, Gao and Pottel (p≤0,05). CONCLUSION in children with normal or slightly impaired renal function Pottel and, especially, Gao formula are better tools to estimate glomerular filtration rate than Schwartz formula. Gao formula’s results in our patients do not significantly differ from isotopic GFR results. J Am Soc Nephrol, 2009 Mar;20(3):629-37. doi: 10.1681/ASN.2008030287. Epub 2009 Jan 21. New equations to estimate GFR in children with CKD. Schwartz G.J. et al..;. Kidney Int. 2013 Mar;83(3):524-30. doi: 10.1038/ki.2012.388. Epub 2012 Dec 19.Comparison of the glomerular filtration rate in children by the new revised Schwartz formula and a new generalized formula.Gao A1, Cachat F, Faouzi M, Bardy D, Mosig D, Meyrat BJ, Girardin E, Chehade H. A simple height-independent equation for estimating glomerular filtration rate in children; Hans Pottel, Liesbeth Hoste, Frank Martens ; Pediatr Nephrol June 2012, Volume 27, Issue 6, pp 973-979 Table 5. Comparison of eGFR by Schwartz, Gao and Pottel (p ≤ 0,05). p eGFR by Schwartz vs. eGFR by Gao0,0000004 eGFR by Schwartz vs. eGFR by Pottel0,000589 eGFR by Gao vs. eGFR by Pottel0,225444 p Isotopic GFR vs. eGFR by Schwartz0,0000002 Isotopic GFR vs. eGFR by Gao0,126863 Isotopic GFR vs. eGFR by Pottel0,033333