Christiane Knepper1, Helmut Ellemunter2, Johannes Eder2, Katharina Niedermayr2, Bettina Haerter3, Philipp Hofer4, Sabine Scholl-Bürgi1, Thomas Müller1, Peter Heinz-Erian5. 1. Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria. 2. Department of Pediatrics III, Cystic Fibrosis Center, Medical University of Innsbruck, Innsbruck, Austria. 3. Department of General and Transplant Surgery, Division of Pediatric Surgery, Medical University of Innsbruck, Innsbruck, Austria. 4. Division of Medical Statistics and Informatics, Medical University of Innsbruck, Innsbruck, Austria. 5. Department of Pediatrics I, Medical University of Innsbruck, Innsbruck, Austria. Electronic address: peter.heinz-erian@tirol-kliniken.at.
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.
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.