Table 1 Patient’s characteristics upon intensive care unit admission (first 24 h)

Age, year

57 (53–68)

63 (54–70)

55 (49–61)

59 (53–66)

0.109

Male gender, n (%)

64 (80)

18 (82)

15 (75)

31 (82)

0.812

BMI, kg/m²

29 (26–32)

28 (26–31)

30 (28–33)

27 (25–32)

0.261

SAPS2

33 (25–40)

32 (27–39)

33 (29–41)

33 (24–40)

0.758

SOFA

7 (4–9)

7 (4–10)

7 (3–10)

7 (4–8)

0.797

Symptoms duration prior ICU, days

8 (6–11)

9 (7–14)

8 (6–10)

9 (7–12)

0.100

 Active smoking, n (%)

4 (5)

2 (9)

1 (5)

1 (3)

0.542

 Chronic hypertension, n (%)

30 (38)

9 (41)

11 (55)

10 (26)

0.093

 Diabetes mellitus, n (%)

21 (26)

6 (27)

6 (30)

9 (24)

0.866

 Chronic respiratory disease, n (%)

10 (13)

6 (27)

2 (10)

2 (5)

0.042

 Chronic cardiac disease, n (%)

16 (20)

6 (27)

2 (10)

8 (21)

0.367

 Immunosuppression, n (%)

9 (11)

2 (9)

2 (10)

5 (13)

0.873

 Temperature ≥ 38.5 °C, n (%)

20 (25)

3 (14)

6 (30)

11 (29)

0.677

 Respiratory rate, min⁻¹

30 (24–35)

30 (27–38)

25 (20–30)

31 (25–37)

0.008

 Mean arterial blood pressure, mmHg

69 (59–82)

61 (55–74)

65 (60–82)

73 (61–83)

0.072

 Lymphocyte count, 10⁻⁹/l

0.82 (0.63–1.19)

0.82 (0.56–0.99)

1.12 (0.67–1.41)

0.76 (0.58–1.17)

0.261

 Creatinine, μmol l⁻¹

87 (67–118)

91 (72–138)

78 (66–108)

86 (62–109)

0.387

 PaO₂/FiO₂, mmHg

130 (101–178)

134 (101–172)

172 (112–230)

127 (100–159)

0.221

 Invasive mechanical ventilation, n (%)

56 (70)

15 (68)

16 (80)

25 (66)

0.520

 High flow nasal oxygenation, n (%)

9 (11)

4 (18)

0 (0)

5 (13)

0.155

 Oxygen mask, n (%)

15 (19)

3 (14)

4 (20)

8 (21)

0.767

Organ support within 24 h

 Vasopressors, n (%)

44 (55)

13 (59)

12 (60)

19 (50)

0.693

Renal replacement therapy, n (%)

1 (3)

0 (0)

0 (0)

1 (3)

0.640