Endocrine Abstracts

Objective: Hyponatraemia is the most common electrolyte disturbance encountered in patients – yet its management remains challenging and variable. We audit the management of hyponatraemia in a busy district general hospital, focusing on length of stay (LOS), readmissions and mortality.

Methodology: A retrospective analysis was carried out of 30 consecutive inpatients alerted by the hospital biochemistry department with a sodium concentration of ≤135 mmol/l. The results were grouped into: mild (130–135 mmol/l), moderate (125–129 mmol/l) and severe (<125 mmol/l), Investigations assessed included: paired serum and urine osmolalities, urine sodium, cortisol, TSH, fluid status, fluid balance and medicines review. Outcomes assessed included LOS, readmission and mortality rate.

Results: Thirty patients (12 male, 18 female) with a mean age (±SD) of 75 (±16) years were included. The majority of patients (90%) had moderate to severe hyponatraemia with an equal representation of acute versus chronic hyponatraemia. Two thirds of patients with hyponatraemia were on medications exacerbating this, with only half of these having their offending drugs withheld. The full diagnostic work-up was only carried out in 10% of patients. Out of the thirty patients, three patients (10%) were admitted to ITU and four (13%) died in hospital. The median LOS was 12 days (IQR 7.75–24.25). In comparison, the hospital median LOS for all other acute admissions (both medical and surgical) during the same period was 1 day (IQR 0–5; P<0.001). Similarly the mortality and readmission rates between the hyponatraemia patients and other acute hospital admissions were 13% versus 3.6% (P=0.008) and 26% versus 14% (P=0.061) respectively.

Conclusion: Hyponatraemia management remains challenging with a high variability and poor adherence to the European guidelines. In addition, we have demonstrated that hyponatraemia is associated with longer LOS and higher rates of mortality and readmission in patients. A specific hospital protocol on hyponatraemia management is being introduced to improve variability in diagnostic work-up.