To investigate the occurrence of hyponatremia in elderly patients with corona virus disease 2019 (COVID-19) admitted to the emergency department.

Data of 159 patients with COVID-19 admitted to the Emergency Department of the Second Hospital of Tianjin Medical University during December 26, 2022 and January 5, 2023 were retrospectively analyzed. According to serum sodium ion level, all patients were divided into eunatremia group and hyponatremia group. Clinical symptoms, medical history, laboratory test results, clinical classification and severity were compared between the two groups. T test was used to compare the measurement data, and χ² test was used to compare the counting data.

Hyponatremia was developed in 65 out of 159 patients, with an incidence of 40.9%, and mild hyponatremia was the most popular (73.85%). Compared with the eunatremia group, patients in hyponatremia group were older, the proportion of women was higher, the symptoms such as fever and anorexia were more popular, and the proportions of patients with hypertension, coronary atherosclerotic heart disease, type 2 diabetes, and chronic kidney disease were higher (t=6.257; χ²=5.122, 4.924, 11.610, 9.803, 6.409, 6.183, 4.078; P < 0.05 or P < 0.01); The percentage of neutrophils, C-reactive protein, D-dimer, and N-terminal pro brain natriuretic peptide levels were higher, while blood sodium concentration and plasma osmotic pressure were lower (t=3.540, 4.420, 3.243, 4.488, -20.050, -15.142; P < 0.01); The proportion of patients with moderate, severe, and critical conditions significantly increased, and the proportion of patients recommended for hospitalization by emergency doctors was higher (χ²=38.868, 35.688; P < 0.01).

The incidence of hyponatremia in elderly COVID-19 patients is high, and COVID-19 patients with hyponatremia have more complications, stronger inflammatory reactions, and more severe conditions, so active treatment should be carried out to reduce the risk of death.