Table 1.
Baseline characteristics and laboratory findings of the patients at the time of admission to the intensive care unit
| Sodium group | ||||||
|---|---|---|---|---|---|---|
| Moderate to severe hyponatremia (n = 111) | Mild hyponatremia (n = 112) | Normonatremia (n = 247) | Mild hypernatremia (n = 49) | Moderate to severe hypernatremia (n = 50) | Total (n = 569) | |
| Age (years) | 63.2 ± 14.94 | 64.3 ± 15.37 | 63.9 ± 14.38 | 60.9 ± 16.15 | 59.7 ± 17.46 | 63.2 ± 15.14 |
| Male sex (%) | 56.8 | 61.6 | 62.3 | 61.2 | 56.0 | 60.5 |
| Enrollment year (%) | ||||||
| 2010 | 15.3 | 13.4 | 14.6 | 14.3 | 10.0 | 14.1 |
| 2011 | 29.7 | 33.0 | 32.4 | 16.3 | 32.0 | 30.6 |
| 2012 | 33.3 | 34.8 | 35.6 | 46.9 | 40.0 | 36.4 |
| 2013 | 21.6 | 18.8 | 17.4 | 22.4 | 18.0 | 19.0 |
| Body weight (kg) | 62.2 ± 11.56 | 64.3 ± 13.19 | 63.6 ± 14.02 | 65.5 ± 12.48 | 62.3 ± 10.62 | 63.5 ± 13.00 |
| Cause of acute kidney injury (%)* | ||||||
| Sepsis | 44.1 † | 55.4 | 49.4 | 55.1 | 36.0* | 48.9 |
| Surgery | 3.6 | 6.2 | 11.7 | 8.2 | 8.0 | 8.4 |
| Nephrotoxin | 5.4 | 4.5 | 8.1 | 6.1 | 4.0 | 6.3 |
| Other | 46.8 | 33.9 | 30.8 | 30.6 | 52.0 | 36.4 |
| Dialysis dose (mL/kg/hour) | 41.9 ± 15.43 | 47.7 ± 18.61 | 45.0 ± 16.99 | 46.2 ± 19.19 | 41.7 ± 15.90 | 44.8 ± 17.21 |
| Need for MV (%) | 76.6 | 83.9 | 85.0 | 93.9 | 80.0 | 83.5 |
| Use of vasoactive drugs (%) | 73.0 | 68.8 | 72.1 | 67.3 | 74.0 | 71.4 |
| Chronic kidney disease (%) | 48.6 | 46.4 | 42.5 | 26.5* | 34.0 | 42.4 |
| Charlson Comorbidity Index † | 3.5 ± 2.18 † | 3.3 ± 2.25* | 2.7 ± 2.13 | 2.5 ± 2.05 | 2.5 ± 1.98 | 2.9 ± 2.17 |
| APACHE II score* | 29.6 ± 9.56 | 28.3 ± 7.91 | 28.7 ± 8.00 | 30.6 ± 8.05 | 32.5 ± 8.15 † | 29.3 ± 8.38 |
| Blood findings | ||||||
| Sodium (mmol/L) ‡ | 126.6 ± 3.99 ‡ | 133.2 ± 1.09 ‡ | 139.5 ± 2.74 | 146.8 ± 0.92 ‡ | 154.0 ± 4.81 ‡ | 137.6 ± 8.27 |
| Creatinine (mg/dL)* | 3.3 ± 2.01 | 3.7 ± 2.67 † | 3.1 ± 1.61 | 2.8 ± 1.27 | 2.9 ± 1.69 | 3.2 ± 1.94 |
| Albumin (g/dL) | 2.7 ± 0.57 | 2.6 ± 0.52 | 2.7 ± 0.52 | 2.6 ± 0.51 | 2.7 ± 0.50 | 2.7 ± 0.53 |
| Glucose (mg/dL) † | 139 (108–190) | 147 (116–196) | 153 (113–229) | 164 (119–222) | 191 (134–311) † | 152 (115–218) |
| Urine output (mL/2 hours) | 15 (0–70) | 20 (0–55) | 20 (0–90) | 30 (0–118) | 28 (4–64) | 20 (0–78) |
| Fluid balance | ||||||
| During 24 h (mL) ‡ | 808.3 ± 1527.1861 | 1069.0 ± 2242.01 | 1250.7 ± 1971.14 | 1736.9 ± 2378.86 | 2772.3 ± 2555.26 ‡ | 1304.2 ± 2103.42 |
| During 72 h (mL) † | 816.1 ± 2966.11 | 1036.9 ± 3773.28 | 999.2 ± 2854.91 | 1957.4 ± 3839.81 | 2611.9 ± 2918.75 ‡ | 1185.9 ± 3197.57 |
| Onset of dysnatremia (%) | ||||||
| Acute | 19.8 | 34.8 | – | 77.6 | 48.0 | 38.2§ |
| Chronic | 61.3 | 46.4 | – | 10.2 | 30.0 | 43.5 |
| Unknown | 18.9 | 18.8 | – | 12.2 | 22.0 | 18.3 |
| Follow-up duration (days) | 13 (4–49)* | 19 (4–123) | 29 (5–273) | 23 (5–434) | 9 (3–93)* | 19 (4–193) |
Comparisons were evaluated using the chi-squared test for categorical variables, the ANOVA test for normally distributed continuous variables (post hoc analysis of LSD between two groups), and the Kruskal-Wallis test for non-normally distributed continuous variables (Mann–Whitney U test between two groups). The normonatremia group served as a reference for comparison between two groups
* P < 0.05; † P < 0.01; ‡ P < 0.001; § proportion among dysnatremia group
MV mechanical ventilation, APACHE acute physiology and chronic health evaluation