The epidemiology of intensive care unit-acquired hyponatraemia and hypernatraemia in medical-surgical intensive care units

Table 2 Multivariable analyses of patient characteristics*

	Acquire hyponatraemia		Acquire hypernatraemia
Characteristic	Odds ratio (95% CI)	P Value	Odds ratio (95% CI)	P value
Age (for each 10 year increase)	0.93 (0.89 to 0.98)	0.004	NS	NS
Baseline creatinine >100 μmol/L	NS	NS	1.47 (1.31 to 1.65)	<0.001
Admitting diagnosis category			NS	NS
Medical	1.00
Neurological/trauma	1.33 (1.06 to 1.65)	0.012
Surgical	1.26 (1.04 to 1.52)	0.017
APACHE II score (for each additional unit)	1.08 (1.06 to 1.09)	<0.001	1.05 (1.04 to 1.05)	<0.001
Mechanical ventilation	NS	NS	1.30 (1.20 to 1.42)	<0.001
Day of ICU stay (for each additional log unit day^‡)	1.95 (1.81 to 2.10)	<0.001	2.06 (1.95 to 2.17)	<0.001
Minimum Glasgow Coma Scale (for each additional unit)	1.06 (1.03 to 1.08)	<0.001	NS	NS
Glucose level (for each additional 1 mmol/L)	1.07 (1.06 to 1.09)	<0.001	NS	NS
Temperature
35.0 to 37.3°C^†	1.00		1.00
>37.3°C	1.36 (1.10 to 1.69)	0.005	1.30 (1.16 to 1.45)	<0.001
<35.0°C	1.36 (1.08 to 1.70)	0.008	1.28 (1.14 to 1.44)	<0.001
Serum potassium
3.5 to 5.0 mmol/L^†	1.00		1.00
>5.0 mmol/L	1.67 (1.42 to 1.97)	<0.001	1.05 (0.93 to 1.19)	0.421
<3.5 mmol/L	1.01 (0.90 to 1.14)	0.846	1.49 (1.40 to 1.59)	<0.001
Level of care	NS	NS
Full care			1.00
Full care, but no CPR			1.23 (1.09 to 1.39)	0.001
Comfort care			1.35 (1.07 to 1.70)	0.010

*Time-independent (age, baseline creatinine, random glucose) and time-dependent (minimum Glasgow coma scale, glucose level, Acute Acute Physiology and Chronic Health Evaluation (APACHE) II score, mechanical ventilation, day of intensive care unit (ICU) stay, temperature, serum potassium, level of care) characteristics included in multivariable models.
†Patients with this factor served as the reference group
‡Length of ICU stay was highly skewed and time unit day was log transformed.
CI = confidence interval, CPR = cardiopulmonary resuscitation, NS = not significant.

ISSN: 1364-8535