Table 1 Baseline characteristics of the patients

Age ≥75 years

63 (38.7)

69 (33.7)

132 (35.9)

 Male

124 (76.1)

158 (77.1)

282 (76.6)

 Female

39 (23.9)

47 (22.9)

86 (23.4)

Current smoker

46 (28.2)

72 (35.1)

118 (32.1)

Pack-years of smoking, mean (SD), no.

58.2 (29.2)

59.5 (25.8)

59.0 (27.1)

COPD exacerbations in the past 12 months, mean (SD), no.

1.1 (1.6)

1.5 (1.9)

1.3 (1.8)

Very severe COPD: <30% of the predicted normal FEV₁

18 (11.0)

37 (18.0)

55 (14.9)

Severe COPD: 30 to <50% of the predicted normal FEV₁

70 (42.9)

99 (48.3)

169 (45.9)

Moderate COPD: 50 to <80% of the predicted normal FEV₁

56 (34.4)

57 (27.8)

113 (30.7)

Mild COPD: ≥80% of the predicted normal FEV₁

19 (11.7)

12 (5.9)

31 (8.4)

 Immobilization^c

1 (0.6)

65 (31.7)

66 (17.9)

 Cancer^d

6 (3.7)

6 (2.9)

12 (3.3)

 History of VTE

0 (0)

9 (4.4)

9 (1.3)

 Surgery^e

0 (0)

1 (0.5)

1 (0.3)

 Obstructive sleep apnea

36 (22.1)

20 (9.8)

56 (15.2)

 Congestive heart failure

25 (15.3)

23 (11.2)

48 (13.0)

 Hormone therapy

3 (1.8)

2 (1.0)

5 (1.4)

 Dyspnea

163 (100)

203 (99.0)

366 (99.5)

 Heart rate >100/min

0 (0)

127 (62.0)

127 (34.5)

 Systolic blood pressure <100 mm Hg

3 (1.8)

8 (3.9)

11 (16.2)

 Spo₂ <90% (N=365)

62 (38.3)

83 (40.9)

145 (39.7)

 Temperature ≥38°C

0 (0)

1 (0.5)

1 (0.3)

 Increased sputum volume

59 (36.2)

69 (33.7)

128 (34.8)

 Purulent sputum

11 (6.7)

13 (6.3)

24 (6.5)

 Hemoptysis

2 (1.2)

1 (0.5)

3 (0.8)

 Signs of DVT

0 (0)

0 (0)

0 (0)

 Creatinine >1.5 mg/dL

4 (2.5)

2 (1.0)

6 (1.6)

 Hemoglobin, mean (SD), g/dL

14.4 (1.9)

14.1 (2.2)

14.3 (2.1)

 Short-acting inhaled beta2-agonists

159 (97.5)

203 (99.0)

362 (98.4)

 Short-acting inhaled anticholinergics

163 (100)

205 (100)

368 (100)

 Systemic corticosteroids

135 (82.8)

165 (80.5)

300 (81.5)

 Antibiotics

113 (69.3)

134 (65.4)

247 (67.1)

 Pharmacological thromboprophylaxis (LMWH)

163 (100)

205 (100)

368 (100)