Prevalence of hyponatremia among medically hospitalized patients and associated outcomes: a retrospective cohort study

Abstract

BACKGROUND: Hyponatremia is a common electrolyte disturbance among hospitalized patients and is linked to increased mortality as well as poor outcomes. OBJECTIVES: Study the prevalence of hyponatremia among medically admitted patients and the outcomes associated with hyponatremia. DESIGN: Retrospective cohort SETTING: Medical ward at tertiary hospital setting PATIENTS AND METHODS: The study included adult (≥18 years) hospitalized patients in general medical wards. Three readings of serum sodium level were taken (initial sodium level, nadir during admission, and before discharge). SAMPLE SIZE AND BASIS: The sample size of 350 was determined based on a presumed 35% incidence of hyponatremia among hospitalized patients, with a 5% error margin. MAIN OUTCOME MEASURES: The prevalence of hyponatremia among medically hospitalized patients and association with health outcomes including length of hospital stay, inpatient mortality, 90-days readmission and 1-year mortality. RESULTS: In this study, 736 patients met the inclusion criteria. Of these, 377 (51.2%) had hyponatremia on admission, increasing to 562 (76.35%) during hospitalization. Mild hyponatremia was observed in 49.6% (n=365), moderate in 13.6% (n=100), and severe in 13.2% (n=97). Severe hyponatremia patients were significantly older (P