Pediatric Nephrology

, 24:67

Human renal function maturation: a quantitative description using weight and postmenstrual age

Authors

  • Malin M. Rhodin
    • Department of Pharmaceutical Biosciences, Division of Pharmacokinetics and Drug Therapy, Faculty of Pharmacy Uppsala University
    • Department of AnesthesiologyUniversity of Auckland
    • C/-PICUAuckland Children’s Hospital
  • A. Michael Peters
    • Department of Applied PhysiologyBrighton and Sussex University Hospitals NHS Trust
  • Malcolm G. Coulthard
    • Paediatric NephrologyRoyal Victoria Infirmary
  • Barry Wilkins
    • Paediatric Intensive Care UnitThe Children’s Hospital at Westmead
  • Michael Cole
    • Northern Institute for Cancer ResearchUniversity of Newcastle
  • Etienne Chatelut
    • EA3035 Université Paul-Sabatier and Institut Claudius-Regaud
  • Anders Grubb
    • Department of Clinical ChemistryUniversity Hospital
  • Gareth J. Veal
    • Northern Institute for Cancer ResearchUniversity of Newcastle
  • Michael J. Keir
    • Department of Medical PhysicsMedical School, University of Newcastle
  • Nick H. G. Holford
    • Department of Pharmacology and Clinical PharmacologyUniversity of Auckland
Original Article

DOI: 10.1007/s00467-008-0997-5

Cite this article as:
Rhodin, M.M., Anderson, B.J., Peters, A.M. et al. Pediatr Nephrol (2009) 24: 67. doi:10.1007/s00467-008-0997-5

Abstract

This study pools published data to describe the increase in glomerular filtration rate (GFR) from very premature neonates to young adults. The data comprises measured GFR (using polyfructose, 51Cr-EDTA, mannitol or iohexol) from eight studies (n = 923) and involved very premature neonates (22 weeks postmenstrual age) to adulthood (31 years). A nonlinear mixed effects approach (NONMEM) was used to examine the influences of size and maturation on renal function. Size was the primary covariate, and GFR was standardized for a body weight of 70 kg using an allometric power model. Postmenstrual age (PMA) was a better descriptor of maturational changes than postnatal age (PNA). A sigmoid hyperbolic model described the nonlinear relationship between GFR maturation and PMA. Assuming an allometric coefficient of 3/4, the fully mature (adult) GFR is predicted to be 121.2 mL/min per 70 kg [95% confidence interval (CI) 117–125]. Half of the adult value is reached at 47.7 post-menstrual weeks (95%CI 45.1–50.5), with a Hill coefficient of 3.40 (95%CI 3.03–3.80). At 1-year postnatal age, the GFR is predicted to be 90% of the adult GFR. Glomerular filtration rate can be predicted with a consistent relationship from early prematurity to adulthood. We propose that this offers a clinically useful definition of renal function in children and young adults that is independent of the predictable changes associated with age and size.

Keywords

Allometry Fat-free mass Body composition Glomerular filtration rate Lean body weight Postmenstrual age Renal function

Abbreviations

BMI

Body mass index

BSA

Body surface area

δ

Asymmetry parameter for the sigmoid hyperbolic model

Ffat

Fraction of fat mass

FFM

Fat-free mass

GFR

Glomerular filtration rate

Hill

An exponent describing the steepness of the sigmoid hyperbolic model (taken from the equation describing the oxygen dissociation curve originally described by Hill in 1910)

NFM

Normal fat mass

NONMEM

Computer software for nonlinear mixed effects modelling

PMA

Postmenstrual age

PNA

Postnatal age

PWR

Power exponent

TM50

The maturation half time, i.e. the time to reach 50% of mature function

VPC

Visual predictive check

Copyright information

© IPNA 2008