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Serum creatinine concentration in very-low-birth-weight infants from birth to 34-36 wk postmenstrual age
David A Bateman1, William Thomas2, Elvira Parravicini1
1Department of Pediatrics, Columbia University Medical Center, New York, New York.
Insights
Serum creatinine (s[Cr]) reference ranges for premature infants are influenced by gestational age (GA). This study establishes GA-specific nomograms for s[Cr] in very-low-birth-weight (VLBW) infants, aiding in accurate interpretation.
Area of Science:
- Neonatal physiology
- Pediatric nephrology
- Biostatistics
Background:
- Accurate serum creatinine (s[Cr]) reference ranges are crucial for very-low-birth-weight (VLBW) infants.
- Physiologic changes in early life necessitate GA-specific reference values.
Purpose of the Study:
- To establish gestational age (GA)-specific reference ranges for serum creatinine (s[Cr]) in VLBW infants.
- To characterize the dynamic changes in s[Cr] during the first months of life in relation to GA.
Main Methods:
- Retrospective analysis of 218 appropriate-for-gestational age (GA) VLBW infants without renal impairment risk factors.
- Classification into GA groups: 25-27, 28-29, and 30-33 weeks.
- Application of mixed-effects regression models to estimate s[Cr] means and 95th prediction intervals from birth to 34-36 weeks postmenstrual age (PMA).
Main Results:
- Three distinct phases of s[Cr] change observed: initial rise, decline, and equilibrium.
- Phase characteristics, including duration and magnitude of s[Cr] rise, varied significantly with GA.
- A steady-state equilibrium (Phase III) was reached around 34-36 weeks PMA, with similar s[Cr] across GA groups.
Conclusions:
- GA-specific nomograms for s[Cr] were developed, reflecting distinct developmental phases.
- These reference ranges provide a quantitative tool for interpreting s[Cr] trends in VLBW infants.
- The findings aid in the assessment of renal function in this vulnerable population.
Background:
Serum creatinine (s[Cr]) reference ranges for very-low-birth-weight (VLBW) infants must account for physiologic changes in the first months of life.
Methods:
We retrospectively identified a sample of 218 appropriate-for-gestational age (GA) VLBW infants without risk factors for renal impairment, and classified into one of three GA groups: 25-27, 28-29, and 30-33 wk. We observed three phases of s[Cr] change (initial, decline, and equilibrium), whose characteristics varied by GA group. We used mixed-effects regression models to estimate mean and upper 95th prediction interval of s[Cr] for each GA group from birth to 34-36 wk post menstrual age (PMA).
Results:
In phase I, s[Cr] increased after birth, then returned slowly to baseline. The duration of phase I and the magnitude of s[Cr] rise decreased with increasing GA. In phase II, s[Cr] declined abruptly at a rate that increased with GA. A gradual transition to phase III, a steady-state equilibrium with similar s[Cr] among GA groups, began at approximately 34-36 wk PMA. We constructed GA group-specific nomograms depicting s[Cr] behaviour across the three phases.
Conclusion:
The reference ranges derived from a sample of infants without risk factors for renal impairment provide a context for quantitative interpretation of s[Cr] trends in VLBW infants.
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