Research Article: Electrolyte imbalances in an unselected population in an emergency department: A retrospective cohort study

Date Published: April 25, 2019

Publisher: Public Library of Science

Author(s): Kiarash Tazmini, Ståle H. Nymo, William E. Louch, Anette H. Ranhoff, Erik Øie, Chiara Lazzeri.


Although electrolyte imbalances (EIs) are common in the emergency department (ED), few studies have examined the occurrence of such conditions in an unselected population.

To investigate the frequency of EI among adult patients who present to the ED, with regards to type and severity, and the association with age and sex of the patient, hospital length of stay (LOS), readmission, and mortality.

A retrospective cohort study. All patients ≥18 years referred for any reason to the ED between January 1, 2010, and December 31, 2015, who had measured blood electrolytes were included. In total, 62 991 visits involving 31 966 patients were registered.

EIs were mostly mild, and the most common EI was hyponatremia (glucose-corrected) (24.6%). Patients with increasing severity of EI had longer LOS compared with patients with normal electrolyte measurements. Among all admitted patients, there were 12928 (20.5%) readmissions within 30 days from discharge during the study period. Hyponatremia (glucose-corrected) was associated with readmission, with an adjusted odds ratio (OR) of 1.25 (95% CI, 1.18–1.32). Hypomagnesemia and hypocalcemia (albumin-corrected) were also associated with readmission, with ORs of 1.25 (95% CI, 1.07–1.45) and 1.22 (95% CI, 1.02–1.46), respectively. Dysnatremia, dyskalemia, hypercalcemia, hypermagnesemia, and hyperphosphatemia were associated with increased in-hospital mortality, whereas all EIs except hypophosphatemia were associated with increased 30-day and 1-year mortality.

EIs were common and increasing severity of EIs was associated with longer LOS and increased in-hospital, 30-days and 1-year mortality. EI monitoring is crucial for newly admitted patients, and up-to-date training in EI diagnosis and treatment is essential for ED physicians.

Partial Text

Electrolyte imbalance (EI) is common in hospitalized patients as well as in the general population and is associated with increased morbidity and mortality [1–9]. Clinically important EIs include dysnatremia, dyskalemia, dyscalcemia, dysmagnesemia, and dysphosphatemia. The prevalence of hyponatremia in the emergency department (ED) is reported to range from 2.3–44%, while prevalence of hypernatremia is 1.1–4.4%, hypokalemia 10.2–39%, hyperkalemia 0.8–13%, and albumin-corrected hypercalcemia 0.7–7.5% [1, 2, 6, 10–13].

This is the first study of a non-selected, adult ED patient population describing the prevalence of EI according to type, severity, and associations to outcomes such as LOS, readmission, and mortality. Nearly half of the patients exhibited at least one type of EI, but most were mild. Increasing severity of EI was associated with longer LOS, increased in-hospital, 30-day and 1-year mortality.

Our results demonstrate that EIs are common in patients admitted to an ED at a local urban hospital, and that patients with EI have an increased risk of prolonged LOS, readmission, and mortality. Thus, EIs increase consumption of health care resources. EIs may be reflect serious underlying conditions or the EI in itself may contribute to the increased risk of prolonged LOS, readmission, and mortality. It is therefore crucial that health personnel are effectively trained in the diagnosis and management of EIs. We further suggest that future studies should investigate whether an increased focus on EI detection, follow-up, and treatment can decrease the risk of prolonged LOS, readmission, and mortality.