Table 1 Primary baseline demographic and clinical characteristics of the participants

Baseline characteristics

Age (years)

77.9 ± 11.6

76.2 ± 10.2

Male, n (%)

12 (63.2)

413 (71.0)

Admissions for AECOPD in year prior, n (%)

0

444 (76.3)

16 (84.2)

1

90 (15.5)

2 (10.5)

≥ 2

48 (8.2)

1 (5.3)

Monitoring parameters at admission

Temperature (degrees Celsius)

36.2 ± 0.9

36.9 ± 0.8

Respiratory rate (beat/min)

27.4 ± 6.3

22.7 ± 6.2

Level of consciousness using the AVPU system, n (%)

 A

8 (42.1)

486 (83.6)

 V

3 (15.8)

35 (6.0)

 P

2 (10.5)

27 (4.6)

 U

6 (31.6)

33 (5.7)

Laboratory findings

PH

7.2 ± 0.1

7.3 ± 0.1

PCO₂ (mmHg)

87.4 ± 38.2

71.5 ± 17.1

PO₂ (mmHg)

64.4 (53.1–91.2)

60.4 (45.0–81.1)

PaO₂/FiO₂

176.4 (99.0–240.0)

191.1 (139.0–253.4)

BE (mmol/L)

5.2 (-5.2–9.4)

8.3 (-4.7–12.3)

Lactic acid (mmol/L)

2.7 (1.4–4.8)

1.4 (0.9–2.4)

Lactic dehydrogenase (IU/L)

335.1 (246.8–600.2)

265.0 (208.4–418.5)

Potassium (mmol/L)

4.6 ± 0.7

4.2 ± 0.7

Magnesium (mmol/L)

1.0 ± 0.1

0.9 ± 0.1

Albumin (g/L)

32.6 ± 5.2

36.0 ± 5.2

Albumin/Globulin ratio

0.9 ± 0.3

1.1 ± 0.3

Blood amylase (U/L)

86.0 (60.5–116.5)

63.0 (45.0–84.8)

Creatinine (μmol/L)

81.6 (66.5–161.9)

74.5 (58.4–97.9)

Blood urea nitrogen (mmol/L)

10.5 (7.9–14.2)

6.5 (4.9–8.7)

C-reactive protein (mg/L)

47.5 (23.9–81.6)

18.4 (4.7–56.0)

White blood cell count (× 10⁹/L)

14.7 ± 6.4

10.3 ± 6.3

Lymphocyte count (× 10⁹/L)

1.2 (0.7–1.8)

0.9 (0.6–1.3)

Neutrophils count (× 10⁹/L)

11.7 ± 4.9

8.3 ± 5.7

Red blood cell count (× 10¹²/L)

4.0 ± 0.5

4.7 ± 2.9

Haematocrit (%)

37.8 ± 3.9

42.7 ± 7.4

Haemoglobin (g/L)

116.4 ± 12.9

135.8 ± 23.8

Platelet count (× 10⁹/L), n (%)

 < 100

2 (10.5)

53 (9.5)

 ≥ 100, < 300

12 (63.2)

444 (79.6)

 ≥ 300

5 (26.3)

61 (10.9)

Mean platelet volume (fL)

10.1 ± 1.0

10.6 ± 1.2

Platelet distribution width (%)

11.2 ± 2.1

12.5 ± 2.9

Comorbidities, n (%)

Pneumonia

7 (36.8)

267 (45.9)

Hydropneumothorax

0 (0.0)

4 (0.7)

Heart failure, coronary heart disease

3 (15.8)

137 (23.5)

Hypertension

0 (0.0)

20 (3.4)

Diabetes

0 (0.0)

4 (0.7)

Respiratory cancer

1 (5.3)

8 (1.4)

Chronic kidney failure

0 (0.0)

3 (0.5)

Pulmonary thromboembolism

2 (0.3)

0 (0.0)

Deep vein thrombosis

2 (0.3)

0 (0.0)

Intervention measures, n (%)

Non-invasive mechanical ventilation

6 (31.6)

207 (35.6)

Invasive mechanical ventilation

11 (57.9)

126 (21.6)

Outcomes, n (%)

Death in emergency department

6 (31.6)

0 (0.0)

ICU admission

11 (57.9)

161 (27.7)