Intensive Care Medicine

, Volume 36, Issue 2, pp 304–311

Incidence and prognosis of dysnatremias present on ICU admission

  • Georg-Christian Funk
  • Gregor Lindner
  • Wilfred Druml
  • Barbara Metnitz
  • Christoph Schwarz
  • Peter Bauer
  • Philipp G. H. Metnitz
Original

Abstract

Purpose

Dysnatremias are common in patients admitted to the intensive care unit (ICU). Whether the presence of disorders of sodium balance on ICU admission is independently associated with excess mortality is unknown. We hypothesized that dysnatremias at the time of ICU admission are independent risk factors for increased mortality in critically ill patients.

Methods

We conducted a retrospective study in 77 medical, surgical, and mixed ICUs in Austria, with a database of 151,486 adults admitted consecutively over a period of 10 years (1998–2007).

Results

Most patients (114,170, 75.4%) had normal sodium levels (135 ≤ Na ≤ 145 mmol/L) on ICU admission. The frequencies of borderline (130 ≤ Na < 135 mmol/L), mild (125 ≤ Na < 130 mmol/L), and severe hyponatremia (Na < 125 mmol/L) were 13.8%, 2.7%, and 1.2%, respectively. The frequencies of borderline (145 < Na ≤ 150 mmol/L), mild (150 < Na ≤ 155 mmol/L), and severe hypernatremia (Na > 155 mmol/L) were 5.1%, 1.2%, and 0.6%, respectively. All types and grades of dysnatremia were associated with increased raw and risk-adjusted hospital mortality ratios. Multiple logistic regression analysis showed an independent mortality risk rising with increasing severity of both hyponatremia and hypernatremia. Odds ratios and 95% confidence interval (CI) for borderline, mild, and severe hyponatremia were 1.32 (1.25–1.39), 1.89 (1.71–2.09), and 1.81 (1.56–2.10), respectively. Odds ratios and 95% CI for borderline, mild, and severe hypernatremia were 1.48 (1.36–1.61), 2.32 (1.98–2.73), and 3.64 (2.88–4.61), respectively.

Conclusions

Our results suggest that both hypo- and hypernatremia present on admission to the ICU are independent risk factors for poor prognosis.

Keywords

Hyponatremia Hypernatremia Sodium Outcome Epidemiology 

Supplementary material

134_2009_1692_MOESM1_ESM.doc (128 kb)
Supplementary material 1 (DOC 128 kb)

Copyright information

© Copyright jointly hold by Springer and ESICM 2009

Authors and Affiliations

  • Georg-Christian Funk
    • 1
  • Gregor Lindner
    • 2
  • Wilfred Druml
    • 3
  • Barbara Metnitz
    • 4
  • Christoph Schwarz
    • 5
  • Peter Bauer
    • 4
  • Philipp G. H. Metnitz
    • 2
  1. 1.Department of Respiratory and Critical Care MedicineOtto Wagner SpitalViennaAustria
  2. 2.Department of Anesthesiology and General Intensive Care MedicineMedical University of ViennaViennaAustria
  3. 3.Department of Nephrology and DialysisMedical University of ViennaViennaAustria
  4. 4.Department of Medical StatisticsMedical University of ViennaViennaAustria
  5. 5.Third Medical DepartmentKrankenhaus der ElisabethinenLinzAustria

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