<b><i>Introduction:</i></b> There is large variability in kidney function and injury in neonates with neonatal encephalopathy (NE) treated with therapeutic hypothermia (TH). Acute kidney injury (AKI) definitions that apply categorical approaches may lose valuable information about kidney function in individual patients. Centile serum creatinine (SCr) over postnatal age (PNA) may provide more valuable information in TH neonates. <b><i>Methods:</i></b> Data from seven TH neonates and one non-TH-treated, non-NE control cohorts were pooled in a retrospective study. SCr centiles over PNA, and AKI incidence (definition: SCr ↑≥0.3 mg/dL within 48 h, or ↑ ≥1.5 fold vs. the lowest prior SCr within 7 days) and mortality were calculated. Repeated measurement linear models were applied to SCr trends, modeling SCr on PNA, birth weight or gestational age (GA), using heterogeneous autoregressive residual covariance structure and maximum likelihood methods. Findings were compared to patterns in the control cohort. <b><i>Results:</i></b> Among 1,136 TH neonates, representing 4,724 SCr observations, SCr (10th–25th–50th–75th–90th–95th) PNA centiles (day 1–10) were generated. In TH neonates, the AKI incidence was 132/1,136 (11.6%), mortality 193/1,136 (17%). AKI neonates had a higher mortality (37.2–14.3%, <i>p</i> &#x3c; 0.001). Median SCr patterns over PNA were significantly higher in nonsurvivors (<i>p</i> &#x3c; 0.01) or AKI neonates (<i>p</i> &#x3c; 0.001). In TH-treated neonates, PNA and GA or birth weight explained SCr variability. Patterns over PNA were significantly higher in TH neonates to controls (801 neonates, 2,779 SCr). <b><i>Conclusions:</i></b> SCr patterns in TH-treated NE neonates are specific. Knowing PNA-related patterns enable clinicians to better assess kidney function and tailor pharmacotherapy, fluids, or kidney supportive therapies.

Many neonates undergoing whole body hypothermia (WBH) following moderate to severe perinatal asphyxia may also suffer from renal impairment. While recent data suggest WBH-related reno-protection, differences in serum creatinine (Scr) patterns to reference patterns were not yet reported. We therefore aimed to document Scr trends and patterns in asphyxiated neonates undergoing WBH and compared these to centiles from a reference Scr data set of non-asphyxiated (near)term neonates. Using a systematic review strategy, reports on Scr trends (mean ± SD, median or interquartile range) were collected (day 1–7) in WBH cohorts and compared to centiles of an earlier reported reference cohort of non-asphyxia cases. Based on 13 papers on asphyxia + WBH cases, a pattern of postnatal Scr trends in asphyxia + WBH cases was constructed. Compared to the reference 50th centile Scr values, mean or median Scr values at birth and up to 48 h were higher in asphyxia + WBH cases with a subsequent uncertain declining trend towards, at best, high or high–normal creatinine values afterwards. Such patterns are valuable for anticipating average changes in renal drug clearance but do not yet cover the relevant inter-patient variability observed in WBH cases, as this needs pooling of individual Screa profiles, preferably beyond the first week of life.

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Many neonates undergoing whole body hypothermia (WBH) following moderate to severe perinatal asphyxia suffer from renal impairment. While recent data suggest a WBH-related reno-protection, the differences in serum creatinine (Scr) patterns to reference patterns were not yet reported. We therefore aimed to document Scr trends and patterns in asphyxiated neonates undergoing WBH, and compared these to centiles reference Scr dataset of non-asphyia neonates. Using a systematic review strategy, reports on Scr trends (mean &plusmn; SD, or median and range) were collected (day 1-7) in WBH cohorts, and compared to centiles of an earlier reported reference cohort of non-asphyxia cases. Based on 13 papers on asphyxia+WBH cases, a pattern on postnatal Scr trends in asphyxia+WBH cases was constructed. Compared to the reference cohort, mean or median Scr values at birth (&gt;90th centile) and the first two days of WBH (&gt;75th centile) remained clinical relevantly higher in asphyxia+WBH cases, with a subsequent decline to reach at best high or high normal creatinine values (all &gt;50th centile, but mainly &gt;75th centile) from day 4 onwards. Such patterns are valuable to anticipate average changes in renal clearance capacity relevant for pharmacotherapy, but do not yet cover the relevant inter-patient variability observed in WBH cases.