# Drug-Induced Hyponatremia as a Cause of Emergency Department Attendance

## TL;DR

This study examines patients with drug-induced low sodium levels in emergency departments, finding that thiazide diuretics are a common cause and that taking many medications increases the risk of returning within 30 days.

## Contribution

The study identifies polypharmacy as an independent risk factor for 30-day revisits due to drug-induced hyponatremia.

## Key findings

- Thiazide diuretics were the most frequently implicated drug class in cases of drug-induced hyponatremia.
- Polypharmacy was the only factor significantly associated with 30-day revisits in multivariable analysis.
- The study population was predominantly elderly women with a mean age of 80.5 years.

## Abstract

Background: Hyponatremia is one of the most common electrolyte disturbances in emergency departments. This study aimed to describe the characteristics of patients presenting with drug-induced hyponatremia and analyse factors associated with 30-day revisits. Methods: Retrospective observational study including adult patients who attended the emergency department for drug-induced hyponatremia between 2020 and 2024. Results: 141 patients were analysed (mean age 80.5 years; 78% women). Thiazide diuretics were the most frequently implicated pharmacological class (50.3%). In univariable analyses, polypharmacy, dementia, and treatment changes at discharge were associated with a higher risk of revisit for hyponatremia. In the multivariable model, only polypharmacy remained significantly associated with 30-day revisits. Conclusions: Thiazide diuretics were the leading drug-related cause of hyponatremia in the emergency setting. Polypharmacy was identified as an independent factor associated with increased revisit risk, underscoring the need for systematic medication review and close clinical follow-up after hospital discharge.