Endocrine Abstracts

Background: Hyponatremia is the most common electrolyte disorder in hospitalized patients with pneumonia. Different studies have shown an association of admission hyponatremia and worse in-hospital outcome, but no data are available about the impact of hyponatremia at discharge on outcome.

Material and methods: Data from a double-blind randomized study including 725 patients hospitalized with community-acquired pneumonia were analyzed. The primary aim of the original study was to compare time to clinical stability upon prednisone treatment as compared to placebo. The aim of this subanalysis was to compare patient-relevant outcomes (i.e. mortality, rehospitalization and recurrence rate) within 180 days in patients with hyponatremia at discharge and normonatremic patients.

Results: Of the 725 patients, 187 (25.8%) were hyponatremic on admission. Of these, 159 (85%) normalized during the hospitalization and 28 (14.9%) were still hyponatremic at discharge. 34 patients developed hyponatremia during hospitalization despite being initially normonatremic. Of these, 17 (50%) were still hyponatremic at discharge. In total, at discharge, 45 (6.2%) patients were hyponatremic and 663 (91.4%) normonatremic. Patients with hyponatremia at discharge had a higher risk of recurrence of pneumonia compared to normonatremic patients at discharge (OR 2.68; 95% CI 1.09-6.95; P=0.037), independently from prednisone treatment (adjusted OR 2.9; 95% CI 1.03-6.96; P=0.027). In contrast, recurrence rate was not affected in patients who were hyponatremic during hospitalization but had normal sodium levels at discharge (P=0.99). There was no association hyponatremia at discharge and mortality or rehospitalization (P> 0.05), but the number of events was low.

Conclusions: Hyponatremia at discharge is associated with an increased risk of recurrence in hospitalized patients with pneumonia, independently from in-hospital sodium levels and prednisone treatment.