Related Experiment Video
Updated: Sep 25, 2025
Transdermal Measurement of Glomerular Filtration Rate in Mechanically Ventilated Piglets
Published on: September 13, 2022
Maturation of GFR in Term-Born Neonates: An Individual Participant Data Meta-Analysis
Nori J L Smeets1,2, Joanna IntHout3, Maurice J P van der Burgh1
1Department of Pharmacology and Toxicology, Radboud Institute of Health Sciences, Radboud University Medical Center, Nijmegen, The Netherlands.
Insights
Glomerular filtration rate (GFR) in healthy newborns doubles in the first five days after birth. This study establishes new reference values and refines the Schwartz equation for estimating neonatal GFR.
Area of Science:
- Neonatal physiology
- Pediatric nephrology
- Biostatistics
Background:
- Existing evidence on GFR maturation in healthy, term-born neonates is inconclusive.
- Accurate GFR reference values are crucial for neonatal care.
- Optimizing creatinine-based GFR estimations is needed.
Purpose of the Study:
- To establish reliable neonatal GFR reference values using individual participant data (IPD) meta-analysis.
- To investigate the maturational pattern of GFR in healthy, term-born neonates.
- To optimize creatinine-based GFR estimations for neonates.
Main Methods:
- Conducted an IPD meta-analysis of reported measured GFR (mGFR) data from healthy, term-born neonates.
- Analyzed 978 mGFR values from 881 neonates, with IPD available for 367.
- Used cubic splines and generalized additive linear mixed models to assess the relationship between postnatal age and GFR.
Main Results:
- Neonatal GFR doubled in the first 5 days post-birth (from 19.6 to 40.6 ml/min/1.73 m²).
- GFR gradually increased to 59.4 ml/min/1.73 m² by 4 weeks of age.
- A coefficient of 0.31 was determined to best fit the Schwartz equation for eGFR estimation.
Conclusions:
- Established biphasic GFR reference values for healthy, term-born neonates, highlighting rapid increase in the first week.
- The updated Schwartz equation with a coefficient of 0.31 can aid in identifying altered GFR.
- Further validation of the proposed eGFR equation in a larger neonatal cohort is necessary for widespread implementation.
Background:
The evidence from individual studies to support the maturational pattern of GFR in healthy, term-born neonates is inconclusive. We performed an individual participant data (IPD) meta-analysis of reported measured GFR (mGFR) data, aiming to establish neonatal GFR reference values. Furthermore, we aimed to optimize neonatal creatinine-based GFR estimations.
Methods:
We identified studies reporting mGFR measured by exogenous markers or creatinine clearance (CrCL) in healthy, term-born neonates. The relationship between postnatal age and clearance was investigated using cubic splines with generalized additive linear mixed models. From our reference values, we estimated an updated coefficient for the Schwartz equation (eGFR [ml/min per 1.73 m2]=(k×height [cm])/serum creatinine [mg/dl]).
Results:
Forty-eight out of 1521 screened articles reported mGFR in healthy, term-born neonates, and 978 mGFR values from 881 neonates were analyzed. IPD were available for 367 neonates, and the other 514 neonates were represented by 41 aggregated data points as means/medians per group. GFR doubled in the first 5 days after birth, from 19.6 (95% CI, 14.7 to 24.6) to 40.6 (95% CI, 36.7 to 44.5) ml/min per 1.73 m2, and then increased more gradually to 59.4 (95% CI, 45.9 to 72.9) ml/min per 1.73 m2 by 4 weeks of age. A coefficient of 0.31 to estimate GFR best fitted the data.
Conclusions:
These reference values for healthy, term-born neonates show a biphasic increase in GFR, with the largest increase between days 1 and 5. Together with the re-examined Schwartz equation, this can help identify altered GFR in term-born neonates. To enable widespread implementation of our proposed eGFR equation, validation in a large cohort of neonates is required.
Related Concept Videos
01:28Glomerular Filtration Rate and its Regulation
GFR regulation involves two primary intrinsic controls: the myogenic and tubuloglomerular feedback mechanisms.
The myogenic...
01:02Renal Drug Excretion: Glomerular Filtration
Drugs gain access to the kidney via the renal artery, which progressively branches off into afferent arterioles....
01:29Physiology of the Genitourinary System I: Renal Blood Flow and Glomerular Filtration
01:15Glomerular Filtration
Components of the Filtration Membrane
The filtration process involves three key layers: the glomerular endothelial cells, the basement membrane, and the podocyte-formed filtration slits.
01:17Factors Affecting Renal Clearance: Renal Impairment
One condition associated with renal failure is uremia. Uremia is characterized by impaired glomerular filtration and fluid accumulation in the body. This condition hinders the renal clearance of drugs, resulting in drug accumulation and potential...
01:26Glomerular Filtration: Net Filtration Pressure
GBHP, with an average value of 55 mmHg, promotes filtration by pushing water and solutes through the filtration membrane. This is balanced by two opposing forces: CHP, a "back pressure" exerted against the filtration membrane by fluid already in the capsular space and renal...