Hyponatraemia during an emergency medical admission as a marker of illness severity & case complexity

Altered sodium balance at time of an emergency medical admission adversely impacts on outcome; whether hyponatraemia is independently associated with outcomes or a surrogate of acute illness severity has been debated. All emergency medical admissions between 2002 and 2017 were studied and a risk score calculated. We compared univarate deciles of admission sodium using a multivariable model, adjusting for risk score. There were 106,586 admissions in 54,928 patients. Patients with lower sodium at admission were older at 66.7 years (IQR 46.7–79.5) compared with 63.3 years (IQR 42.9–78.2) with a longer length of stay (LOS) of 6.8 days (IQR 3.0–14.7) versus 4.9 days (IQR 1.8–10.9). They had a higher 30-day in-hospital mortality at 6.4% vs 4.4% (p