Table 1 Baseline characteristics of the study cohort

Number of patients

1641

547

1094

861

780

246

1395

Age, years

73 (62–79)

75 (66–81)

73 (60–78)

<0.001

74 (65–80)

72 (59–78)

<0.001

75 (68–81)

73 (61–79)

<0.001

Male sex, %

59

58

59

0.48

57

61

0.12

57

59

0.61

Co-morbidities, %

 COPD

34

36

32

0.10

36

31

0.01

43

32

0.001

 CVD

28

30

26

0.07

30

26

0.13

30

27

0.33

 Stroke

12

14

11

0.08

12

12

0.79

13

12

0.66

 Tumour

9

11

8

0.04

10

8

0.16

11

9

0.32

 Renal

5

6

4

0.08

6

4

0.22

7

5

0.26

 Liver

8

9

8

0.25

8

8

0.62

10

8

0.19

 DM

15

13

16

0.13

17

14

0.06

17

15

0.38

Vital signs

 MAP, mmHg

80 (67–93)

70 (54–83)

84 (73–97)

<0.001

77 (60–90)

83 (71–97)

<0.001

67 (50–82)

82 (70–95)

<0.001

 Respiratory rate, breaths/minute

27 (24–32)

28 (24–32)

26 (24–32)

0.01

28 (24–32)

26 (24–32)

0.09

30 (24–32)

26 (24–32)

0.003

 Temperature, °C

36.8 (36.2–38.2)

36.8 (36.2–38.2)

36.8 (36.2–38.1)

0.83

36.8 (36.2–38.2)

36.8 (36.2–38.1)

0.65

37 (36.2–38.2)

36.8 (36.2–38.1)

0.62

 Heart rate, beats/minute

110 (98–126)

110 (99–126)

110 (97–125)

0.20

110 (98–128)

110 (98–124)

0.22

110 (98–126)

110 (98–126)

0.99

 Mental confusion, %

28

46

20

<0.001

37

19

<0.001

66

22

<0.001

Laboratory results

 WBC, ×10⁹/L

11.2 (7.7–15.6)

11.0 (7.6–15.1)

11.2 (7.8–15.6)

0.48

11.2 (7.7–15.5)

11.3 (7.7–15.7)

0.75

11.4 (7.6–16)

11.2 (7.7–15.5)

0.71

 PCT, ng/ml

1.1 (0.9–3.4)

1.3 (0.9–9.4)

1.1 (0.9–3.4)

<0.001

1.1 (0.9–3.4)

1.1 (0.9–3.4)

0.50

1.2 (0.9–3.7)

1.1 (0.9–3.4)

0.15

 PaO₂, mmHg

75 (59–94)

71 (57–89)

77 (60–96)

<0.001

74 (59–92)

76 (59–96)

0.28

69 (55–86)

77 (60–95)

<0.001

 Platelets, ×10⁹/L

184 (135–243)

185 (136–243)

183 (134–244)

0.91

186 (136–243)

183 (134–243)

0.81

188 (142–246)

183 (134–242)

0.73

 Creatinine, μmol/L

100 (75–148)

106 (78–170)

98 (74–136)

<0.001

102 (77–157)

98 (73–136)

0.02

134 (98–228)

96 (72–134)

<0.001

 Bilirubin, μmol/L

12.3 (8.3–18.6)

13.1 (8.1–19.3)

12.0 (8.1–18.3)

0.04

12.2 (8.2–19)

12.5 (8.3–18.3)

0.94

12.2 (8.2–18.7)

12.3 (8.3–18.5)

0.63

 Positive sputum culture

378/1132 (33 %)

143/394 (36 %)

235/738 (32 %)

0.13

209/583 (36 %)

169/549 (31 %)

0.07

73/187 (39 %)

305/945 (32 %)

0.07

 Lactate, mmol/L

2.6 (1.0–5.1)

5.4 (3.1–8.1)

1.6 (0.8–3.3)

<0.001

4.4 (2.5–7.0)

1.2 (0.6–2.5)

<0.001

8.5 (6.6–11.7)

2.1 (0.9–4.0)

<0.001

Multi-lobar opacities, %

40

47

37

<0.001

42

38

0.07

53

38

<0.001

PSI

124 ± 40 (n = 578)

144 ± 36 (n = 199)

113 ± 38 (n = 379)

<0.001

137 ± 38 (n = 278)

111 ± 38 (n = 300)

<0.001

156 ± 37 (n = 92)

117 ± 38 (n = 486)

<0.001

APACHE II

16 (12–21)

20 (15–26)

15 (11–19)

<0.001

18 (14–23)

15 (11–18)

<0.001

22 (17–28)

16 (11–20)

<0.001

CRB-65

2 (1–2)

2 (1–3)

1 (1–2)

<0.001

2 (1–2)

1 (1–2)

<0.001

2 (2–3)

1 (1–2)

<0.001

CRB

1 (0–1)

1 (1–2)

1 (0–1)

<0.001

1 (0–2)

1 (0–1)

<0.001

1 (1–2)

1 (0–1)

<0.001

qSOFA

1 (1–2)

2 (1–2)

1 (1–1)

<0.001

1 (1–2)

1 (1–2)

<0.001

2 (1–2)

1 (1–2)

<0.001

28-day mortality (%)

33

–

–

–

54

11

<0.001

85

24

<0.001