Serum sodium correction rate and the outcome in severe hyponatremia

Study objective

We investigated the serum sodium correction rate on length of hospitalization and survival rate, in severe chronic hyponatremic patients at the Emergency Department (ED).

Design

An observational study using clinical chart review.

Setting

The ED of the University Hospital of Marcianise, Caserta, Italy with approximately 30,000 patients visits a year.

Type of participants

We reviewed sixty-seven patients with severe hyponatremia subdivided in 2 subgroups: group A consisting of 35 patients with serum sodium correction rate < 0.3 mmol/h and group B consisting of 32 patients with serum sodium correction rate between < 0.5 and ≥ 0.3 mmol/h.

Intervention

Emergency patients were evaluated for serum sodium correction rate for hyponatremia by clinical chart review.

Measurements and main results

Severe hyponatremia was defined as a serum sodium level < 120 mmol/l. Mean serum sodium correction rate of hyponatremia was of 0.17 ± 0.09% in group A and 0.41 ± 0.05% in group B (p < 0.001 vs group A). The length of hospital stay was 10.7 ± 3.7 days for group A, and it was significantly decreased to 3.8 ± 0.4 days for group B (p < 0.005 vs group A). In addition we observed that correction rate of hyponatremia in group A was associated with a significantly lower survival rate (25%) in comparison to group B (60%) (p < 0.001 vs group A).Conclusion: We observed that serum sodium correction rate ≥ 0.3 and < 0.5 mmol/h was associated with a shorter length of hospital stay and a major survival rate.