Table 1 Patient characteristics for groups (case: beta-blockers, control: non-beta-blockers)

Age, years, median (quartile 1–3)

71 (63–77)

71 (64–75)

0.82

Female/male

18/56

28/86

0.97

BMI, kg/m², median (quartile 1–3)

23 (22–27)

24 (21–28)

0.82

Comorbidities, n (%)

69 (93.2)

100 (87.7)

0.22

 AF, n (%)

56 (75.7)

80 (70.2)

0.41

 Diabetes mellitus, n (%)

20 (27.0)

29 (25.4)

0.81

 CAD, n (%)

12 (16.2)

14 (12.3)

0.45

 Hypertension, n(%)

42(56.8)

73 (64)

0.32

Pre ICU location, n (%)

 Emergency service

40 (54.1)

55 (48.2)

0.69

 Hospital ward

31 (41.9)

55 (48.2)

 Another ICU

3 (4.1)

4 (3.5)

Reason for ICU admission

 COPD exacerbation

64 (86.5)

101 (88.6)

0.35

 Pneumonia

8 (10.8)

6 (5.3)

 Hemodynamic monitoring

0 (0)

3 (2.6)

 Postoperative respiratory failure

0 (0)

1 (0.9)

 Home ventilator evaluation

2 (2.7)

0 (0)

 Sepsis, n (%)

50 (67.6)

76 (66.7)

0.90

 Septic shock, n (%)

12 (16.2)

13 (11.4)

0.34

 ICU admission APACHE-II value

19 (17–23)

20 (16–24)

0.88

 ICU admission CRP mg/L

39 (14–91)

41 (14–125)

0.33

 Peak of CRP mg/L median

64 (23–130)

110 (30–178)

0.08

 Microbiologic culture, n (%)

51 (68.9)

67 (58.8)

0.16

   Positive culture n (%)

18 (35.3)

27 (23.7)

0.58

   Resistant pathogen, rate

14/18

23/27

0.43

Arterial blood gases analysis on admission ICU

   pH, median (quartile 1–3)

7.28 (7.25-7.37)

7.32 (7.25-7.40)

0.08

   PaCO₂, mmHg, median (quartile 1–3)

72 (54–86)

73 (59–84)

0.78

   PaO₂/FiO_2, median (quartile 1–3)

160 (130–211)

168 (116–230)

0.65

Type of acute respiratory failure, n(%)

 PaO₂/FiO₂ <300

15 (20.3)

19 (16.7)

0.50

 PaO₂/FiO₂ < 300 and PaCO₂ > 45 mmHg

46 (62.2)

79 (69.3)

 PaCO₂ > 45 mmHg

13 (17.6)

16 (14.0)