[Hyponatremia in elderly patients admitted in an acute geriatric care unit. prevalence and prognosis]. / Hiponatremia en pacientes ancianos ingresados en una Unidad de Agudos de Geriatría. Prevalencia y pronóstico.

BACKGROUND AND OBJECTIVE: In order to analyze the prevalence of hyponatremia in in-hospital elderly patients and its prognosis factor value, we performed a transversal prospective study in an Acute Geriatric Unit (AGU). PATIENTS AND METHODS: Two hundred and sixty in-hospital patients were collected prospectively in an AGU. Sociodemographic and lab data were collected as well as the Barthel, Pfeiffer and Charlson tests. A questionnaire was performed in hospital. Hyponatremia was considered when the plasmatic sodium was ≤134 mmol/l. RESULTS: The sample consisted of 137 women (52.7%) and 123 men (47.3%). Mean age was 83.6 years (SD 7.9). Mean plasmatic sodium values were 137.3 mmol/l (range 112-168). Emergency lab tests showed 60 patients with hyponatremia (23.7%), 35 (13.6%) in the AGU. Cardiopulmonary were the most related diseases. Mean hospital length of stay was 12.8 days (SD 12.8). In-hospital mortality was 12.9%. We observed a statistic relationship between the presence of hyponatremia and a greater mean length of stay (15.53 vs 11.99 days, P=.003). No relationship was found between hyponatremia and mortality (15 vs 12.7%, P=.588). CONCLUSION: Hyponatremia in patients admitted in an AGU is a prevalent disorder related with a greater hospital length of stay, but not with mortality.