ESPN 53rd Annual Meeting

ESPN 2021


 
Creatinine-based GFR-estimating equations in children with overweight and obesity
MARK J.C.M. VAN DAM 1 HANS POTTEL 2 ANITA C.E. VREUGDENHIL 1

1- CENTRE FOR OVERWEIGHT ADOLESCENT AND CHILDREN’S HEALTHCARE (COACH), DEPARTMENT OF PEDIATRICS, SCHOOL OF NUTRITION AND TRANSLATIONAL RESEARCH IN METABOLISM (NUTRIM), MAASTRICHT UNIVERSITY MEDICAL CENTRE +, MAASTRICHT, THE NETHERLANDS
2- DEPARTMENT OF PUBLIC HEALTH AND PRIMARY CARE, KU LEUVEN CAMPUS KULAK KORTRIJK, KORTRIJK, BELGIUM
 
Introduction:

With the increasing prevalence of childhood obesity and related development of chronic kidney disease (CKD), there is a critical need to understand how best to assess kidney function in children with obesity. Since direct measurement of glomerular filtration rate (GFR) is still considered to be too invasive in children for routine clinical use, estimated GFR (eGFR) is preferred. With serum creatinine (SCr) being recommended as marker of first choice for GFR evaluation, we evaluated and compared creatinine-based GFR estimating equations in children with overweight and obesity.

Material and methods:

In this retrospective, cross-sectional study, 600 children with overweight and obesity (53.5% female; mean age 12.20 ± 3.28 years; mean BMI z-score 3.31 ± 0.75) were included from the Centre for Overweight Adolescent and Children’s Healthcare (COACH).

Results:

Serum creatinine (SCr), normalized using Q-age polynomials, obtained from reference values, results in median and mean SCr/Q value close to ‘1’ for all age-groups, and 96.5% of the children have a SCr/Q within the reference band [0.67 – 1.33], corresponding to the 2.5th and 97.5th percentile. There is a significant difference between boys and girls (0.97 vs. 1.01) in mean SCr/Q (p = 0.0006). eGFR Schwartz and Schwartz-Lyon and age were inversely correlated, whereas eGFR iCARE showed an increasing eGFR-age pattern. eGFR EKFC and modified CKD-EPI showed no age-dependency, but the distribution of eGFR-values was not symmetrical. eGFR FAS-age, FAS-height and adjusted-creatinine revised Lund-Malmö (LMREV-18) showed a relatively symmetrical distribution and no age-dependency.

Conclusions:

Serum creatinine (SCr) values of children with overweight and obesity are mostly within the normal reference range for children without CKD. Normalization of SCr using reference Q-age polynomials works very well in this cohort. After evaluation of the different equations, we suggest that FAS-age, FAS-height and LMREV-18 are the preferred creatinine-based GFR-estimating equations in children with overweight and obesity.