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Hyponatraemia at hospital admission is a predictor of overall mortality
Author(s) -
Balling L.,
Gustafsson F.,
Goetze J. P.,
Dalsgaard M.,
Nielsen H.,
Boesgaard S.,
Bay M.,
Kirk V.,
Nielsen O. W.,
Køber L.,
Iversen K.
Publication year - 2015
Publication title -
internal medicine journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.596
H-Index - 70
eISSN - 1445-5994
pISSN - 1444-0903
DOI - 10.1111/imj.12623
Subject(s) - medicine , emergency medicine , hospital admission , intensive care medicine
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 G reater C openhagen between 1 A pril 1998 and 31 M arch 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 ‐ N a + <137 mmol/ L at hospital admission was present in 1105 (37.3 %) patients. Results One‐year mortality was higher for hyponatraemic patients than for normonatraemic patients: 27.5% versus 17.7%. Moreover, hyponatraemia was an independent predictor of short and long‐term all‐cause mortality after 1 year and after the entire observation period respectively: hazard ratio ( HR ) 1.6 (95 % confidence interval (CI) 1.4–1.9, P < 0.0001) and HR 1.4 (95 % CI 1.3–1.6, P < 0.0001). Patients with hyponatraemia had longer hospitalisations than patients with normonatraemia: 7.6 (±0.38) days vs 5.6 (±0.21) days, P < 0.001. There was no interaction between hyponatraemia at admission and any admission diagnoses ( P > 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.