Background Serum creatinine (Scr) centile values were recently described in a cohort of 1136 (near)-term neonates that underwent therapeutic hypothermia (TH) because of moderate to severe hypoxic-ischemic encephalopathy. Recent methodological progress enables conversion of these Scr centiles to estimated glomerular filtration rate (eGFR) values. Methods Scr centiles in the TH dataset during the first 10 days of life were converted to eGFR values, using the Schwartz formula, with the Smeets k-value (0.31) and fixed body length (50 cm) to generate postnatal reference eGFR values, centiles, and an equation for median eGFRs. These findings were compared to published eGFR data in term controls. Results A polynomial function was estimated: <InlineEquation ID="IEq1"> <EquationSource Format="TEX">$\mathrm{eGFR} \left(\frac{\mathrm{mL}}{\mathrm{min}}\bullet 1.73{ \mathrm{m}}^{2}\right)=9.1667+7.1173 x -0.3439{x}^{2},(x=\mathrm{days})$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="normal">eGFR</mi> <mfenced close=")" open="("> <mfrac> <mi mathvariant="normal">mL</mi> <mi mathvariant="normal">min</mi> </mfrac> <mo>∙</mo> <mn>1.73</mn> <msup> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mn>2</mn> </msup> </mfenced> <mo>=</mo> <mn>9.1667</mn> <mo>+</mo> <mn>7.1173</mn> <mi>x</mi> <mo>-</mo> <mn>0.3439</mn> <msup> <mrow> <mi>x</mi> </mrow> <mn>2</mn> </msup> <mo>,</mo> <mrow> <mo stretchy="false">(</mo> <mi>x</mi> <mo>=</mo> <mi mathvariant="normal">days</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> for eGFR in TH neonates. The median eGFR increases 2- to threefold over the first week (day 1: 16.1; day 2: 19.4; day 7: 41.2 mL/min∙1.73 m2), while the polynomial function does not fully reflect the interindividual variability in eGFR values (intra-day variability is also 2- to threefold). Patterns in acute kidney injury (AKI) TH cases differ significantly from non-AKI TH cases. Based on pooling of published eGFR data, this was compared to a function in healthy term neonates: <InlineEquation ID="IEq2"> <EquationSource Format="TEX">$\mathrm{eGFR} \left(\frac{\mathrm{mL}}{\mathrm{min}}\bullet 1.73 {\mathrm{m}}^{2}\right)=14.2167+6.7644 x-0.3901{x}^{2}(x=\mathrm{days})$</EquationSource> <EquationSource Format="MATHML"><math> <mrow> <mi mathvariant="normal">eGFR</mi> <mfenced close=")" open="("> <mfrac> <mi mathvariant="normal">mL</mi> <mi mathvariant="normal">min</mi> </mfrac> <mo>∙</mo> <mn>1.73</mn> <msup> <mrow> <mi mathvariant="normal">m</mi> </mrow> <mn>2</mn> </msup> </mfenced> <mo>=</mo> <mn>14.2167</mn> <mo>+</mo> <mn>6.7644</mn> <mi>x</mi> <mo>-</mo> <mn>0.3901</mn> <msup> <mrow> <mi>x</mi> </mrow> <mn>2</mn> </msup> <mrow> <mo stretchy="false">(</mo> <mi>x</mi> <mo>=</mo> <mi mathvariant="normal">days</mi> <mo stretchy="false">)</mo> </mrow> </mrow> </math></EquationSource> </InlineEquation> (day 1: 20; day 2: 26; day 7: 42 mL/min/1.73 m2). Conclusions Based on a pooled dataset in TH cases, we converted Scr centiles to eGFR centiles. Based on median values, this resulted in a polynomial function in TH cases, compared to healthy term neonates. This eGFR function enables precision pharmacotherapy for GFR-cleared drugs in this vulnerable population. Graphical abstract

Progression of the estimated glomerular filtration rate in asphyxiated neonates undergoing therapeutic hypothermia during the first 10 days of life

期刊论文
出版模式：

开放获取
发表日期：

2025年9月18日

查看全文

Karel Allegaert,
Julia Macente,
Djalila Mekahli,
John van den Anker,
Pieter Annaert,
Anne Smits

摘要

Background

Serum creatinine (Scr) centile values were recently described in a cohort of 1136 (near)-term neonates that underwent therapeutic hypothermia (TH) because of moderate to severe hypoxic-ischemic encephalopathy. Recent methodological progress enables conversion of these Scr centiles to estimated glomerular filtration rate (eGFR) values.

Methods

Scr centiles in the TH dataset during the first 10 days of life were converted to eGFR values, using the Schwartz formula, with the Smeets k-value (0.31) and fixed body length (50 cm) to generate postnatal reference eGFR values, centiles, and an equation for median eGFRs. These findings were compared to published eGFR data in term controls.

Results

A polynomial function was estimated: $\mathrm{eGFR} \left(\frac{\mathrm{mL}}{\mathrm{min}}\bullet 1.73{ \mathrm{m}}^{2}\right)=9.1667+7.1173 x -0.3439{x}^{2},(x=\mathrm{days})$ $eGFR (\frac{mL}{\min} ∙ 1.73 m^{2}) = 9.1667 + 7.1173 x - 0.3439 x^{2}, (x = days)$ for eGFR in TH neonates. The median eGFR increases 2- to threefold over the first week (day 1: 16.1; day 2: 19.4; day 7: 41.2 mL/min∙1.73 m²), while the polynomial function does not fully reflect the interindividual variability in eGFR values (intra-day variability is also 2- to threefold). Patterns in acute kidney injury (AKI) TH cases differ significantly from non-AKI TH cases. Based on pooling of published eGFR data, this was compared to a function in healthy term neonates: $\mathrm{eGFR} \left(\frac{\mathrm{mL}}{\mathrm{min}}\bullet 1.73 {\mathrm{m}}^{2}\right)=14.2167+6.7644 x-0.3901{x}^{2}(x=\mathrm{days})$ $eGFR (\frac{mL}{\min} ∙ 1.73 m^{2}) = 14.2167 + 6.7644 x - 0.3901 x^{2} (x = days)$ (day 1: 20; day 2: 26; day 7: 42 mL/min/1.73 m²).

Conclusions

Based on a pooled dataset in TH cases, we converted Scr centiles to eGFR centiles. Based on median values, this resulted in a polynomial function in TH cases, compared to healthy term neonates. This eGFR function enables precision pharmacotherapy for GFR-cleared drugs in this vulnerable population.

Graphical abstract