Table 3 Demographic characteristic, laboratory results, symptoms, physical examinations

Age (years)

83.9 ± 3.3

85.6 ± 3.8

0.001

Female n (%)

329 (58.3%)

25 (55.6%)

0.716

BMI

23.2 ± 3.4

21.6 ± 2.8

0.002

Major comorbidity, n (%)

 Cardiovascular disease n (%)

400 (70.9%)

36 (80%)

0.194

 Respiratory disease n (%)

243 (43.1%)

22 (48.9%)

0.450

 Neurological diseases n (%)

137 (24.5%)

13 (28.9%)

0.508

 Malignancy n (%)

36 (6.4%)

7 (15.6%)

0.021

 Varicose n (%)

34 (6.0%)

1 (2.2%)

0.291

 Liver and kidney disease n (%)

20 (3.6%)

4 (8.9%)

0.077

Surgery in 3 months n (%)

42 (7.4%)

4 (8.9%)

0.725

Trauma in 3 months n (%)

49 ( 8.7%)

4 (8.9%)

0.966

Central venous catheterization

0 (0.0%)

0 (0.0%)

-

Smoking n (%)

182 (37.1%)

13 (31.7%)

0.494

Immobilization more than 3 days n (%)

400 (73.9%)

27 (62.8%)

0.113

Laboratory examination

 Anemia

152 (27.8%)

20 (46.5%)

0.009

 Thrombocytopenia

37 (6.7%)

6 (13.6%)

0.086

 White blood cell > 10*10⁹/L

112 (20.1%)

13 (30.2%)

0.115

 PaO₂ < 60 mmHg n (%)

97 (19.5%)

17 (47.2%)

< 0.001

 eGFR < 60 mL/min/1.73m2 n (%)

186 (34.4%)

23 (56.1%)

0.005

 Elevated cardiac biomarkers n (%)

266 (47.2%)

25 (55.6)

0.278

 Elevated BNP or NT-proBNP n (%)

35 (63.1%)

29 (64.4%)

0.859

 Elevated CTN n (%)

327 (58%)

30 (66.7%)

0.255

Symptoms and signs

 Cough n (%)

273 (48.5%)

22 (48.9%)

0.959

 Sputum n (%)

237 (42.1%)

21 (46.7%)

0.551

 Dyspnea n (%)

357 (63.4%)

28 (62.2%)

0.874

 Chest pain n (%)

145 (25.8%)

13 (28.9%)

0.645

 Hemoptysis n (%)

30 (5.3%)

4 (8.9%)

0.317

 Palpitation n (%)

57 (10.1%)

5 (11.1%)

0.833

 Syncope n (%)

47 (8.3%)

3 (6.7%)

0.693

 Temperature > 37.3◦C n (%)

42 (7.5%)

3 (6.7%)

0.842

 Pulse > 110/min n (%)

35 (6.3%)

7 (15.9%)

0.016

 SBP < 100 mmHg n (%)

6 (1.6%)

3 (6.7%)

0.019

 DBP < 60 mmHg n (%)

24 (4.3%)

6 (13.3%)

0.007

 Respiratory rate > 20/min n (%)

174 (31.0%)

15 (34.1%)

0.672