title: Risk factors for late-onset hyponatremia and its influence on neonatal outcomes in preterm infants.
abstract: Late-onset hyponatremia (LOH), hyponatremia occurring after two weeks of age with the achievement of full feeding, is the result of a negative sodium balance caused by inadequate salt intake or excessive salt loss due to immature renal or intestinal function in preterm infants. The aims of our study were to identify the risk factors for LOH and its influence on neonatal outcomes. This was a retrospective cohort analysis of 161 preterm infants born before 34 weeks of gestation between June 2009 and December 2010 at Seoul National University Hospital. LOH was defined as a sodium level ≤ 132 mEq/L or 133-135 mEq/L with oral sodium supplementation. LOH occurred in 49 (30.4%) of the studied infants. A lower gestational age, a shorter duration of parenteral nutrition, the presence of respiratory distress syndrome, the use of furosemide, and feeding with breast milk were significant risk factors for LOH. In terms of neonatal outcomes, the infants with LOH had longer hospital stays and higher risks of bronchopulmonary dysplasia and retinopathy of prematurity requiring surgery. LOH lasting at least 7 days significantly increased moderate to severe bronchopulmonary dysplasia, periventricular leukomalacia, and extra-uterine growth retardation. LOH is commonly observed in preterm infants; it may be a risk factor for bronchopulmonary dysplasia and retinopathy of prematurity or a marker of illness severity.
authors.affiliation: Department of Pediatrics, Jeju National University Hospital, Jeju, Korea.
authors.forename: Yoon-Joo
authors.identifier: 0000-0002-2832-036X
authors.initials: YJ
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Seoul National University Boramae Hospital, Seoul, Korea. ; Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Jin A
authors.identifier: 0000-0002-9194-0529
authors.initials: JA
authors.lastname: Lee
authors.affiliation: Department of Biostatistics, Seoul National University Boramae Hospital, Seoul, Korea.
authors.forename: Sohee
authors.initials: S
authors.lastname: Oh
authors.affiliation: Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Chang Won
authors.initials: CW
authors.lastname: Choi
authors.affiliation: Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea. ; Department of Biostatistics, Seoul National University Boramae Hospital, Seoul, Korea.
authors.forename: Ee-Kyung
authors.initials: EK
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea. ; Department of Biostatistics, Seoul National University Boramae Hospital, Seoul, Korea.
authors.forename: Han-Suk
authors.initials: HS
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea.
authors.forename: Beyong Il
authors.initials: BI
authors.lastname: Kim
authors.affiliation: Department of Pediatrics, Seoul National University College of Medicine, Seoul, Korea. ; Department of Biostatistics, Seoul National University Boramae Hospital, Seoul, Korea.
authors.forename: Jung-Hwan
authors.initials: JH
authors.lastname: Choi
mesh_terms: D001997:Bronchopulmonary Dysplasia / Q000209:etiology; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007010:Hyponatremia / Q000209:etiology*; D007231:Infant, Newborn; D007234:Infant, Premature; D016015:Logistic Models; D008297:Male; D012189:Retrospective Studies; D012307:Risk Factors
keywords: Hyponatremia; Outcome; Premature Infant; Prematurity; Risk Factors
references.citation: Biol Neonate. 2001 Feb;79(2):109-12
references.pmid: 11223652
references.citation: Am J Respir Crit Care Med. 2001 Jun;163(7):1723-9
references.pmid: 11401896
references.citation: Arch Dis Child Fetal Neonatal Ed. 2002 Mar;86(2):F120-3
references.pmid: 11882555
references.citation: Ann Clin Lab Sci. 2002 Summer;32(3):231-43
references.pmid: 12175085
references.citation: Acta Paediatr Hung. 1983;24(1):23-35
references.pmid: 6613573
references.citation: Arch Dis Child. 1984 Oct;59(10):945-50
references.pmid: 6497431
references.citation: J Pediatr. 1985 Jun;106(6):990-4
references.pmid: 3998955
references.citation: Arch Dis Child. 1986 Oct;61(10):1030-2
references.pmid: 3777985
references.citation: Monogr Neural Sci. 1986;12:179-84
references.pmid: 3796644
references.citation: J Nutr. 1987 Sep;117(9):1623-8
references.pmid: 3655941
references.citation: Pediatr Res. 1988 Jan;23(1):86-8
references.pmid: 3340451
references.citation: J Pediatr. 1988 Oct;113(4):789-90
references.pmid: 3171808
references.citation: Pediatr Res. 1990 Mar;27(3):260-3
references.pmid: 2138727
references.citation: Pediatr Nephrol. 1993 Dec;7(6):871-5
references.pmid: 8130123
references.citation: BMJ. 1997 Feb 8;314(7078):404-8
references.pmid: 9040385
references.citation: Clin Biochem. 1997 Jul;30(5):385-9
references.pmid: 9253514
references.citation: Cochrane Database Syst Rev. 2008;(1):CD000503
references.pmid: 18253981
references.citation: Pediatrics. 2009 Nov;124(5):e1014-6
references.pmid: 19858147