La hiponatremia al momento de ingreso como factor de riesgo de mortalidad hospitalaria

Abstract

Background: Patients who develop hyponatremia during their hospitalization have higher hospital mortality. Aim: To determine if the presence of hyponatremia on admission to the emergency room is a risk factor for hospital mortality. Patients and Methods: Two hundred forty fi ve patients consecutively admitted to the emergency room and then transferred to the Medicine Department, where they fi nally died, were matched for age and gender with 245 control subjects admitted to the emergency room and hospitalized in the Medicine Department at the same time, but survived. The dependent variable was death, and the exposure variable was hyponatremia. Admission diagnosis and Charlson comorbidity index was considered as confounding variables. Results: Hyponatremia at admission occurred in 30 and 17% of patients who died and survived, respectively, rendering an adjusted odds ratio for death of 2.13 (95% confi dence intervals = 1.27-3.57). Charlson Comorbidity Index according to age score was higher in subjects with hyponatremia compared to those without hyponatremia (8.1 ± 3.1 and 7.2 ± 2.8; p = 0.01). Multivariate analysis showed that age, gender, length of stay, cause of hospitalization and chronic diseases did not signifi cantly modify the effect of hyponatremia on hospital mortality. Conclusions: Hyponatremia on admission at emergency room had a signifi cant association with hospital mortality. Subjects with hyponatremia had a higher Charlson Comorbidity Index score.