Characteristics | Normonatremia (n = 323) | Hyponatremia (n = 90) | Statistical values | P value |
---|---|---|---|---|
Age (years) | 70.62 ± 9.06 | 72.02 ± 8.82 |  − 1.30 | 0.193 |
Sex [Male n (%)] | 251 (77.7%) | 69 (76.7%) | 0.04 | 0.834 |
Body mass index (BMI) | 22.25 ± 3.38 | 22.22 ± 3.61 | 0.06 | 0.954 |
Smoking |  |  |  − 2.19 | 0.029 |
 Non-smoking | 108 (33.4%) | 41 (45.6%) |  |  |
 Ex-smoking | 76 (23.5%) | 20 (22.2%) |  |  |
 Current-smoking | 139 (43.1%) | 29 (32.2%) |  |  |
GOLD stages |  |  |  − 1.15 | 0.251 |
 Stage I: mild (≥ 80%) | 24 (7.4%) | 10 (11.1%) |  |  |
 Stage II: moderate (50–79%) | 115 (35.6%) | 23 (25.5%) |  |  |
 Stage III: severe (30–49%) | 94 (29.1%) | 25 (27.8%) |  |  |
 Stage IV: very severe (< 30%) without respiratory failure | 26 (8.1%) | 7 (7.8%) |  |  |
 Respiratory failure | 64 (19.8%) | 25 (27.8%) |  |  |
Underlying diseases/co-morbidities | ||||
 Pleural effusion [n, (%)] | 7 (2.2%) | 9 (10.0%) | 11.60 | 0.001 |
 CAP [n, (%)] | 124 (38.4%) | 65 (72.2%) | 32.46 | 0.000 |
 CAD [n, (%)] | 56 (17.3%) | 22 (24.4%) | 2.32 | 0.128 |
 Hypertension [n, (%)] | 124 (38.4%) | 38 (42.2%) | 0.43 | 0.510 |
 T2DM [n, (%)] | 49 (15.2%) | 19 (21.1%) | 1.81 | 0.179 |
 Af [n, (%)] | 11 (3.4%) | 8 (8.9%) | 4.82 | 0.028 |
 CTD [n, (%)] | 2 (0.6%) | 1 (1.1%) | 0.24 | 0.627 |
 Pneumothorax [n, (%)] | 2 (0.6%) | 2 (2.2%) | 1.89 | 0.170 |
Mechanical ventilation (MV) |  |  |  − 1.89 | 0.058 |
 Non-ventilation [n, (%)] | 300 (92.9%) | 78 (86.7%) |  |  |
 NIPPV [n, (%)] | 23 (7.1%) | 11 (12.2%) |  |  |
 IPPV [n, (%)] | 0 (0.0%) | 1 (1.1%) |  |  |