Urine sodium to urine creatinine ratio as a marker of total body sodium in infants with intestinal failure
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Read the article on jpedsurg.org ↗Article · Jan 2022 · 1 min read
In brief
In brief
This study validates urine sodium-to-creatinine ratio (UNa:UCr) as a superior marker of total body sodium status compared to urine sodium alone in infants with intestinal failure. A UNa:UCr >35 predicted adequate growth with 92% sensitivity and correlated better with sodium intake, offering clinicians a practical tool for nutritional management in this vulnerable population.
Written by the GCMD Library team from the article.
Purpose: Urine sodium (UNa) is a measure of total body sodium in infants with intestinal failure (IF) but can be misleading as it does not reflect volume status. Urine sodium to urine creatinine ratio (UNa:UCr) may offer a more accurate measure, but is not routinely used. This study compares UNa:UCr to UNa as a maker of sodium status in infants with IF.
Methods: A retrospective review of infants with IF, from a single centre, from 2018-2020 was conducted (REB H20-00816). IF etiology, intestinal anatomy, nutritional intake, urine electrolytes and anthropometrics were collected. Linear mixed effects models adjusting for repeated measures were used to associate UNa and UNa:UCr with weight gain and sodium intake.
Results: Twenty-two infants with a median gestational age of 31 weeks were included. IF etiology included gastroschisis (41%), necrotizing enterocolitis (23%), and intestinal perforation (14%). Infants had an average of 3 paired UNa and UNa:UCr measures for a total of 74 paired measurements. UNa:UCr more strongly correlated with sodium intake compared to UNa (R=0.25, p=0.032 vs. R=0.10, p=0.38). Overall, neither UNa (p=0.21) nor UNa:UCr (p=0.16) were significantly correlated with weight gain. However, for infants receiving ≤50% nutrition enterally, weight gain correlated with UNa (p=0.01) and UNa:UCr (p=0.01). UNa:UCr >35 predicted adequate growth regardless of enteral intake (92% sensitivity, 59% specificity).
Conclusion: UNa:UCr is a measure of total body sodium that correlates with sodium intake in infants with IF. Our study indicates UNa:UCr >35 is associated with adequate growth and can be used to guide further validation studies.