ESPN 51th Annual Meeting

ESPN 2018


 
THE REVISED SCHWARTZ FORMULA: IS ONE K-COEFFICIENT ADEQUATE FOR ALL CHILDREN?
IBRAHIM GOKCE 1 NESLIHAN CICEK 1 SAFIYE ULKU OZCETIN 1 HARIKA ALPAY 1

1- MARMARA UNIVERSITY MEDICAL SCHOOL, DEPARTMENT OF PEDIATRIC NEPHROLOGY, ISTANBUL, TURKEY
 
Introduction:

 

Glomerular filtration rate (GFR) is the most useful indicator of kidney function and kidney disease progression. Plasma creatinine based formulas to estimate GFR are recommended for regular clinical use in children by several clinical guidelines. The Schwartz formula was devised for this reason in the mid-1970s in children but recent data suggested that this formula overestimates GFR. In 2009, Schwartz et al. adapted the classical Schwartz formula(c-Schwartz) but used only one k-coefficient (k = 0.413) for all ages of children from infancy to adolescence. For that reason, in this study, we aimed to evaluate the reliability and applicability of the revised Schwartz formula(r-Schwartz) in children with reflux nephropathy (RN).

Material and methods:

 

Our study included 154 patients with RN between 4-18 years of age who were followed up in our outpatient clinic. Glomerular filtration rate was calculated by using 24-hour urine samples (24-hr CCl), the c-Shwartz formula and r-Schwartz formula for all patients.

Results:

 

Eighty nine patients (57.8%) were girl, 65 (42.2%) were boy and the mean age was 10,42±3,34 years. The mean 24-hr CCl, GFR calculated with c-Shwartz formula and with r-Schwartz formula were 144.97±40.39, 158.51±22.84 and 115.92±17.46 ml/min/1.73m2 respectively. Both Schwartz formulas showed good correlation with 24-hr CCl (p<0.001) but the c-Shwartz formula was more correlated with 24-hr CCl (r:0.414) than the r-Schwartz formula (r:0.343).

Conclusions:

 

Herein we found that the c-Shwartz formula was more correlated with 24-hr CCl than the r-Schwartz formula. Revised Schwartz formula calculated by using only one k-coefficient is not reliable enough to estimate GFR in children including the period of infancy and adolescence. Further studies of children and adolescents are needed to evaluate the applicability of the r-Schwartz formula.