Background
Methods
Patient recruitment
Collected data
Statistical analysis
Results
Population characteristics
All patients (n = 147) | Group A (n = 20) | Group B (n = 41) | Group C (n = 86) |
P
a
| ||
---|---|---|---|---|---|---|
Age (years) | n = 147 | 69.6 ± 13.3 | 68.8 ± 14.5 | 69.5 ± 13.2 | 69.9 ± 13.3 | .95 |
Males/Females (%) | n = 147 | 42.2/57.8 | 35.0/65.0 | 48.8/51.2 | 40.7/59.3 | .57 |
Weight (kg) | n = 116 | 64.6 ± 16.5 | 62.3 ± 14.6 | 67.8 ± 18.0 | 63.4 ± 16.1 | .39 |
BMI (kg/m2) | n = 79 | 24.1 ± 5.8 | 22.0 ± 5.1 | 25.2 ± 7.2 | 24.0 ± 5.1 | .37 |
Plasma sodium at admission (mmol/l) | n = 147 | 121 ± 10.4 | 110 ± 11.7 | 119 ± 8.4 | 126 ± 8.5 | <.001 |
Nadir plasma sodium (mmol/l) | n = 147 | 115 ± 4.7 | 105 ± 3.4 | 113 ± 1.4 | 118 ± 1.0 | <.001 |
Measured plasma osmolality (mosm/l) | n = 50 | 254 ± 18 | 240 ± 13 | 252 ± 12 | 265 ± 18 | <.001 |
Plasma sodium at discharge (mmol/l) | ||||||
- Survivors - Nonsurvivors | n = 111 n = 36 | 132 ± 6.5 132 ± 11.2 | 133 ± 8.6 124 ± 18.4 | 134 ± 8.9 133 ± 13.8 | 131 ± 7.2 132 ± 9.1 | .24 .61 |
Delta plasma sodium (mmol/l) b | n = 147 | 20.8 ± 8.6 | 31.1 ± 6.5 | 23.0 ± 8.2 | 17.4 ± 6.9 | <.001 |
Serum potassium (mmol/l) | n = 147 | 4.2 ± 1.0 | 3.8 ± 1.0 | 4.0 ± 0.9 | 4.4 ± 1.0 | .01 |
Urea (mmol/l) | n = 147 | 10.1 ± 10.4 | 7.0 ± 9.6 | 8.4 ± 9.1 | 11.7 ± 10.9 | .02 |
Plasma creatinine (μmol/l) | n = 147 | 118 ± 134 | 83 ± 115 | 93 ± 84 | 138 ± 153 | .03 |
eGFR (ml/min/1.73 m2) | n = 147 | 100 ± 65.1 | 131 ± 65.3 | 100 ± 58.7 | 93 ± 66.5 | .05 |
Uric acid (μmol/l) | n = 59 | 336 ± 237 | 258 ± 261 | 285 ± 246 | 386 ± 220 | .04 |
Plasma glucose (g/l) | n = 143 | 1.54 ± 1.16 | 1.50 ± 0.58 | 1.32 ± 0.90 | 1.66 ± 1.35 | .08 |
Triglycerides (g/l) | n = 40 | 0.83 ± 0.33 | 0.73 ± 0.30 | 0.88 ± 0.30 | 0.85 ± 0.40 | .51 |
Total protein (g/l) | n = 100 | 62 ± 8.3 | 62 ± 6.1 | 63 ± 9.3 | 62 ± 8.4 | .89 |
Serum albumin (g/l) | n = 110 | 34 ± 6.0 | 36 ± 3.9 | 35 ± 5.7 | 33 ± 6.6 | .19 |
TSH | n = 72 | 3.66 ± 9.1 | 1.71 ± 2.58 | 3.73 ± 10.31 | 4.47 ± 10.2 | .03 |
Plasma cortisol | n = 26 | 230 ± 106 | 247 ± 95 | 191 ± 75 | 240 ± 122 | .59 |
BNP | n = 55 | 453 ± 586 | 537 ± 331 | 382 ± 545 | 472 ± 646 | .27 |
Comorbidities
All patients (n = 147) | Group A (n = 20) | Group B (n = 41) | Group C (n = 86) |
P
a
| |
---|---|---|---|---|---|
Department of hospitalisation | |||||
- Medicine (%) - Surgery (%) - Intensive care (%) | 105 (72.9) 14 (9.7) 25 (17.4) | 13 (68.4) 0 (0) 6 (31.6) | 31 (79.5) 1 (2.6) 7 (18.0) | 61 (70.9) 13 (15.1) 12 (14.0) | .05 |
Charlson comorbidity index | 3.8 ± 3.0 | 2.2 ± 1.9 | 4.0 ± 3.1 | 4.2 ± 3.1 | .02 |
Myocardial Infarction (%) | 31 (21.1) | 2 (10.0) | 11 (26.8) | 18 (20.1) | .34 |
Heart failure (%) | 29 (19.7) | 2 (10.0) | 8 (19.5) | 19 (22.1) | .53 |
Peripheral artery disease (%) | 23 (15.7) | 0 (0) | 9 (22.0) | 14 (16.3) | .07 |
Stroke (%) | 18 (12.2) | 4 (20.0) | 3 (7.3) | 11 (12.8) | .34 |
Dementia (%) | 9 (6.1) | 4 (20.0) | 1 (2.4) | 4 (4.7) | .03 |
Chronic lung disease (%) | 31 (21.1) | 2 (10.0) | 13 (31.7) | 16 (18.6) | .12 |
Chronic liver disease (%) | 12 (8.2) | 1 (5.0) | 1 (2.4) | 10 (11.6) | .21 |
Diabetes (%) | 33 (22.5) | 3 (15.0) | 8 (19.5) | 22 (25.6) | .57 |
Chronic kidney disease (%) | 23 (15.7) | 0 (0) | 7 (17.1) | 16 (18.6) | .10 |
Cancer (%) | 57 (38.8) | 6 (30.0) | 19 (46.3) | 32 (37.2) | .43 |
Symptoms
All patients (n = 147) | Group A (n = 20) | Group B (n = 41) | Group C (n = 86) |
P
a
| ||
---|---|---|---|---|---|---|
Patients with symptoms (%) | n = 147 | 83 (56.5) | 19 (95.0) | 23 (56.1) | 41 (47.7) | <.001 |
Severe neurologic symptoms (%) | n = 147 | 13 (8.8) | 7 (35.0) | 2 (4.9) | 4 (4.7) | .001 |
- Seizure (%) | n = 147 | 9 (6.1) | 4 (20.0) | 1 (2.4) | 4 (4.7) | .03 |
- Coma (%) | n = 147 | 4 (15.0) | 3 (15.0) | 1 (2.4) | 0 (0) | .003 |
Confusion (%) | n = 147 | 42 (28.6) | 10 (50.0) | 11 (26.8) | 21 (24.4) | .08 |
Nausea/vomiting (%) | n = 147 | 17 (11.6) | 3 (15.0) | 6 (14.6) | 8 (9.3) | .50 |
Gait disturbance/Fall (%) | n = 147 | 20 (13.6) | 4 (20.0) | 7 (17.1) | 9 (10.5) | .38 |
Other symptoms (%) | n = 147 | 7 (4.8) | 2 (10.0) | 2 (4.9) | 3 (3.5) | .32 |
Acute vs. chronic severe hyponatraemia
All patients (n = 147) | Group A (n = 20) | Group B (n = 41) | Group C (n = 86) |
P
a
| |
---|---|---|---|---|---|
Timing | |||||
- Present at admission (%) - Acquired in hospital (%) | 95 (64.6) 52 (35.4) | 16 (80.0) 4 (20.0) | 31 (75.6) 10 (24.4) | 48 (55.8) 38 (44.2) | .03 |
Timing | |||||
- Acute (%) - Acute-on-chronic (%) - Chronic (%) - Unknown (%) | 26 (17.7) 28 (19.1) 10 (6.8) 83 (56.5) | 4 (20.0) 0 (0) 1 (5.0) 15 (75.0) | 5 (12.2) 6 (14.6) 3 (7.3) 27 (65.9) | 17 (19.8) 22 (25.6) 6 (7.0) 41 (47.7) | .07 |
Community-acquired vs. hospital-acquired severe hyponatraemia
Aetiological workup
Diagnosis
All patients (n = 147) | Group A (n = 20) | Group B (n = 41) | Group C (n = 86) |
P
a
| |
---|---|---|---|---|---|
Diagnosis | |||||
Unknown (%) | 69 (46.9) | 6 (30.0) | 16 (39.0) | 47 (54.7) | .07 |
Potomania (%) | 8 (5.4) | 3 (15.0) | 3 (7.3) | 2 (2.3) | .04 |
Heart failure (%) | 13 (8.8) | 1 (5.0) | 2 (4.9) | 10 (11.6) | .37 |
Cirrhosis (%) | 4 (2.7) | 0 (0) | 1 (2.4) | 3 (3.5) | .68 |
Diuretics (%) | 6 (4.1) | 1 (5.0) | 1 (2.4) | 4 (4.7) | .82 |
Hypotonic fluids (%) | 3 (2.0) | 0 (0) | 1 (2.4) | 2 (2.3) | 1.0 |
Dehydration (%) | 22 (15.0) | 4 (20.0) | 7 (17.1) | 11 (12.8) | .61 |
CSWS (%) | 2 (1.4) | 0 (0) | 1 (2.4) | 1 (1.2) | .66 |
SIADH (%) | 28 (19.1) | 6 (30.0) | 12 (29.3) | 10 (11.6) | .03 |
Hypothyroidism (%) | 3 (2.0) | 2 (10.0) | 1 (2.4) | 0 (0) | .02 |
Adrenal insufficiency (%) | 4 (2.7) | 1 (5.0) | 0 (0) | 3 (3.5) | .42 |
Treatment (%) | 127 (86.4) | 20 (100) | 37 (90.2) | 70 (81.4) | .06 |
- Fluid restriction (%) - Cause withdrawal (%) - Isotonic saline (%) - Hypertonic saline (%) - Furosemide (%) - Demeclocycline (%) | 93 (63.3) 31 (21.1) 67 (45.6) 16 (10.9) 19 (12.9) 10 (6.8) | 17 (85.0) 8 (40.0) 8 (40.0) 9 (45.0) 2 (10.0) 4 (20.0) | 28 (68.3) 9 (22.0) 22 (53.7) 2 (4.9) 6 (14.6) 4 (9.8) | 48 (55.8) 14 (16.3) 37 (43.0) 5 (5.8) 11 (12.8) 2 (2.3) | .04 .07 .47 <.001 .94 .01 |
Plasma sodium normalisation (%) | 84 (57.1) | 12 (60.0) | 24 (58.5) | 48 (55.8) | .92 |
Death during hospitalisation (%) | 36 (24.5) | 2 (10.0) | 13 (31.7) | 21 (24.4) | .17 |
Death during follow-up (%) | 74 (50.3) | 8 (40.0) | 21 (51.2) | 45 (52.3) | .64 |
Treatment
Mortality
All patients (n = 147) | Hospital-acquired severe hyponatraemia (n = 52) | Community-acquired severe hyponatraemia (n = 95) |
P
*
| |
---|---|---|---|---|
Plasma sodium (mmol/l) | ||||
- on admission - lowest - at discharge - at discharge in survivors - Highest – lowest - Normalisation (%) | 121.5 ± 10.4 114.9 ± 4.7 132.2 ± 7.9 132.9 ± 5.9 20.8 ± 8.6 84 (57.1) | 133.1 ± 5.7 116.4 ± 3.9 130.3 ± 8.8 133.2 ± 6.9 20.0 ± 6.9 25 (48.1) | 115.2 ± 6.0 114.1 ± 4.9 133.2 ± 7.2 132.7 ± 5.6 21.3 ± 9.4 59 (70.2) | <.001 <.001 .07 .84 .39 .12 |
Severe neurologic symptoms (%) | 13 (8.8) | 4 (7.7) | 9 (9.5) | .99 |
Charlson comorbidity index | 3.8 ± 3.0 | 4.92 ± 3.4 | 3,3 ± 2,6 | .005 |
Potential causes of hyponatraemia | 2.9 ± 1.3 | 3.5 ± 1.3 | 2.6 ± 1.3 | <.001 |
Diagnosis | ||||
Unknown (%) | 69 (46.9) | 30 (57,7) | 39 (41.1) | .06 |
Potomania (%) | 8 (5.4) | 1 (1,9) | 7 (7,4) | .26 |
Heart failure (%) | 13 (8.8) | 4 (7,7) | 9 (9,5) | .99 |
Cirrhosis (%) | 4 (2.7) | 0 (0) | 4 (4.2) | .30 |
Diuretics (%) | 6 (4.1) | 1 (1,9) | 5 (5,3) | .42 |
Hypotonic fluids (%) | 3 (2.0) | 3 (5,8) | 0 (0) | .04 |
Dehydration (%) | 22 (15.0) | 7 (13,5) | 15 (15,8) | .81 |
CSWS (%) | 2 (1.4) | 1 (1.9) | 1 (1.1) | .99 |
SIADH (%) | 28 (19.1) | 6 (11,5) | 22 (23,2) | .12 |
Hypothyroidism (%) | 3 (2.0) | 0 (0) | 3 (3.2) | .55 |
Adrenal insufficiency (%) | 4 (2.7) | 3 (5.8) | 1 (1.1) | .13 |
Number of diagnoses reported per patient | 0.65 ± 0.7 | 0.52 ± 0.75 | 0.72 ± 0.69 | .05 |
Urine analysis (%) | 109 (74.2) | 39 (75.0) | 70 (73.7) | .99 |
- Sodium (%) - Osmolality (%) - Urea (%) - Uric Acid (%) | 109 (74.2) 38 (25.9) 102 (69.4) 17 (11.6) | 39 (75.0) 12 (23.1) 37 (71.2) 5 (9.6) | 70 (73.7) 26 (27.4) 65 (68.4) 12 (12.6) | .99 .69 .85 .79 |
Death during hospitalisation (%) | 36 (24.5) | 21 (40.4) | 15 (15.8) | .001 |
Death during follow-up (n = 139) (%) | 74 (50.3) | 35 (70.0) | 38 (42.7) | .003 |
Univariate Cox analysis HR [95CI] |
P
| Multivariate Cox analysisa HR [95CI] |
P
| |
---|---|---|---|---|
Male vs. Female | 0.57 [0.36–0.90] | .02 | 0.69 [0.40–1.20] | .19 |
Age | 0.99 [0.97–1.01] | .37 | ||
Hospital vs. community-acquired hyponatraemia | 2.24 [1.41–3.56] | .001 | 1.23 [0.67–2.27] | .51 |
Chronic vs. acute hyponatraemia | 0.72 [0.28–1.85] | .50 | ||
Symptomatic hyponatraemia | 0.80 [0.51–1.27] | .36 | ||
Severe neurologic symptoms | 0.85 [0.37–1.97] | .71 | ||
Nadir of plasma sodium | 1.02 [0.97–1.08] | .35 | 0.95 [0.89–1.01] | .13 |
Urine analysis | 0.64 [0.39–1.06] | .08 | 0.48 [0.27–0.85] | .01 |
Absence of diagnosis | 1.77 [1.11–2.81] | .02 | 1.07 [0.55–2.07] | .84 |
Number of potential causes | 1.45 [1.23–1.70] | <.001 | 1.07 [0.84–1.35] | .59 |
Treatment for hyponatraemia | 0.34 [0.19–0.60] | <.001 | 0.67 [0.30–1.52] | .34 |
Accuracy of treatment | 0.95 [0.43–2.08] | .90 | ||
Plasma sodium normalisation | 0.61 [0.39–0.97] | .04 | 0.35 [0.20–0.62] | <.001 |
Excessive correction | 0.64 [0.33–1.25] | .19 | 0.76 [0.33–1.77] | .52 |
Charlson comorbidity index | 1.28 [1.19–1.38] | <.001 | 1.23 [1.13–1.34] | <.001 |
Serum albumin (g/l) | 0.91 [0.88–0.95] | <.001 | 0.88 [0.84–0.92] | <.001 |