Borderline hypernatraemia and mortality rates in South African infants: A single-centre observational study

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N Naka
F Solomon
S A Madhi
A Izu
J M Pettifor
Z Dangor
S G Lala


 Background. In children, hypernatraemia occurs most commonly in infants (younger than 1 year). Although hypernatraemia is associated with high mortality and morbidity rates, it is variably defined in the paediatric literature as either serum sodium ≥150 mmol/L or serum sodium >145 mmol/L. In hospitalised adults, a serum sodium level >145 mmol/L but <150 mmol/L (called borderline hypernatraemia) has recently been identified as an independent risk factor for mortality. There are limited data about a potential association between borderline hypernatraemia and mortality in infants. 

Objectives. To determine whether borderline hypernatraemia is associated with increased mortality in hospitalised infants. 

Methods. We conducted a single-centre, retrospective observational study of 8 343 infants admitted to a tertiary-level academic hospital in Johannesburg, South Africa, of whom 254 had borderline hypernatraemia, 376 had hypernatraemia (serum sodium ≥150 mmol/L), and 7 713 did not have hypernatraemia. Mortality rates were reported as odds ratios (ORs) with 95% confidence intervals (CIs). 

Results. In 254 infants with borderline hypernatraemia, 115 (45.3%) were neonates (≤28 days old) and 140 (55.1%) were male. In 139 infants >28 days old with borderline hypernatraemia, the mortality rate (n=9/139; 6.5%) was significantly higher than the mortality rate observed in infants without hypernatraemia (n=194/5 857; 3.3%) (OR 2.02; 95% CI 1.03 - 3.98). 

Conclusion. Borderline hypernatraemia may be a risk factor associated with higher mortality in hospitalised infants. Prospective studies are required to determine whether borderline hypernatraemia contributes independently to mortality risk in hospitalised infants. 

Article Details

How to Cite
Borderline hypernatraemia and mortality rates in South African infants: A single-centre observational study. (2023). South African Journal of Child Health, 17(4), 211-214.

How to Cite

Borderline hypernatraemia and mortality rates in South African infants: A single-centre observational study. (2023). South African Journal of Child Health, 17(4), 211-214.


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