Serum creatinine levels are significantly influenced by renal size in the normal pediatric population.
OBJECTIVE
Clinical and experimental data have shown that differences in nephron endowment result in differences in renal mass and predisposition to chronic renal failure, hypertension, and proteinuria. We hypothesized that a significant proportion of the variance in GFR, as estimated by serum creatinine, is attributable to differences in renal size in normal children.


METHODS
A total of 1748 normal renal ultrasounds that were performed in children older than 6 months were reviewed. For each ultrasound, serum creatinine, serum blood urea nitrogen, and systolic and diastolic office BP were recorded. Renal size was evaluated as a function of renal length and thickness. All data were normalized for height, weight, age, and gender.


RESULTS
When expressed as SD scores, a significant correlation was found between kidney size and serum creatinine (P < 0.0001) and between kidney size and serum blood urea nitrogen (P < 0.002). When dividing kidney size data per quintiles, a difference of 0.51 SD score in serum creatinine was observed between the lowest and highest quintile. No significant correlation was found with office BP measurements.


CONCLUSIONS
These data show that, even in the normal pediatric population, differences in renal function are significantly explained by differences in renal mass. Methodologic limitations of this study are likely to underestimate this relationship.
Di Zazzo
Giacomo
G
Department of Nephrology and Urology, Division of Nephrology and Dialysis, Bambino Gesù Children's Hospital, Rome, Italy.
Stringini
Gilda
G
Matteucci
Maria Chiara
MC
Muraca
Maurizio
M
Malena
Saverio
S
Emma
Francesco
F
D001794:Blood Pressure; D002648:Child; D002675:Child, Preschool; D003404:Creatinine / Q000097:blood*; D005260:Female; D005919:Glomerular Filtration Rate; D006801:Humans; D007223:Infant; D007668:Kidney / Q000033:anatomy & histology* / Q000000981:diagnostic imaging; D008297:Male; D009399:Nephrons / Q000033:anatomy & histology; D009929:Organ Size; D012189:Retrospective Studies; D014463:Ultrasonography
D003404:Creatinine