Hyponatraemia at hospital admission is a predictor of overall mortality

Background Hyponatraemia is a prognostic marker of increased mortality and morbidity in selected groups of hospitalised patients. The aim of the present study was to examine the prevalence and prognostic significance of hyponatraemia at hospital admission in an unselected population with a broad spectrum of medical and surgical diagnoses. Methods Consecutive patients >40 years of age admitted to a general district hospital in Greater Copenhagen between 1 April 1998 and 31 March 1999. Median follow‐up time was 5.16 years (range 0–4372 days). Plasma sodium measurements were available in 2960 patients, and hyponatraemia defined as P‐Na+ 0.05 for all interaction analyses). Conclusion Hyponatraemia is associated with increased all‐cause mortality and longer admission length independently of diagnosis and clinical variables.