Hyponatremia at Hospital Admission is a Predictor of Overall Mortality.
Intern Med J. 2014 Nov 5;
Authors: Balling L, Gustafsson F, Goetze JP, Dalsgaard M, Nielsen H, Boesgaard S, Bay M, Kirk V, Nielsen OW, Køber L, Iversen K
BACKGROUND: Hyponatremia is a prognostic marker of increased mortality and morbidity in selected groups of hospitalized patients. The aim of the present study was to examine the prevalence and prognostic significance of hyponatremia 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 hyponatremia defined as P-Na(+) < 137 mmol/L at hospital admission was present in 1105 (37.3 %) patients.
RESULTS: One year mortality was higher for hyponatremic patients than for normonatremic patients: 27.5 % versus 17.7 %. Moreover, hyponatremia was an independent predictor of short- and long term all-cause mortality after 1 year and after the entire observation period, respectively: HR 1.6 (95 % CI 1.4-1.9, p < 0.0001) and HR 1.4 (95 % CI 1.3-1.6, p < 0.0001). Patients with hyponatremia had longer hospitalizations than patients with normonatremia: 7.6 (± 0.38) days versus 5.6 (± 0.21) days, p < 0.001. There was no interaction between hyponatremia at admission and any admission diagnoses (p > 0.05 for all interaction analyses).
CONCLUSION: Hyponatremia is associated with increased all-cause mortality and longer admission length independently of diagnosis and clinical variables.
PMID: 25370908 [PubMed - as supplied by publisher]