Low Sodium Status in Cystic Fibrosis-As Assessed by Calculating Fractional Na(+) Excretion-Is Associated With Decreased Growth Parameters

J Cyst Fibros. 2016 May;15(3):400-5. doi: 10.1016/j.jcf.2015.12.010. Epub 2016 Jan 6.

Abstract

Background: In CF infants, normonatremic Na(+) depletion (NNaD), identified by fractional Na(+) excretion (FENa) values <0.5%, was recently linked to impaired growth. Our paper investigates the relationship between FENa and growth in CF children >2years.

Methods: FENa values were calculated in 35 CF and 24 control children, and tested for correlations with z-scores for weight, height and BMI.

Results: All CF children and controls had normal plasma Na(+) concentrations. A total of 25 of 35 (71.4%) CF patients had decreased FENa values <0.5% (group I). FENa results of 10 CF patients (group II) and 23/24 controls (group III) were normal. In Na(+)-depleted CF children, compared to normal controls, mean z-scores for weight (-0.18±0.87 vs +1.03±0.57, p<0.001), height (-0.06±0.89 vs +0.53±0.72, p=0.009) and BMI (-0.22±0.87 vs +1.00±1.06, p<0.001) were significantly reduced. Also, we found positive correlations between FENa values and z-scores for weight (r=0.521), height (r=0.292) and BMI (r=0.468), respectively.

Conclusion: NNaD may contribute to poor growth in CF.

Keywords: Cystic fibrosis; Fractional sodium excretion; Growth retardation; Normonatremic sodium depletion.

MeSH terms

  • Austria / epidemiology
  • Body Height
  • Body Mass Index
  • Body Weight
  • Child
  • Child, Preschool
  • Cross-Sectional Studies
  • Cutaneous Elimination
  • Cystic Fibrosis* / blood
  • Cystic Fibrosis* / diagnosis
  • Cystic Fibrosis* / epidemiology
  • Cystic Fibrosis* / physiopathology
  • Diarrhea* / complications
  • Diarrhea* / physiopathology
  • Female
  • Growth Disorders* / blood
  • Growth Disorders* / diagnosis
  • Growth Disorders* / etiology
  • Humans
  • Hyponatremia* / diagnosis
  • Hyponatremia* / etiology
  • Hyponatremia* / physiopathology
  • Intestinal Elimination
  • Male
  • Prospective Studies
  • Sodium* / blood
  • Sodium* / metabolism
  • Statistics as Topic
  • Sweating*

Substances

  • Sodium