Table 1 Patient characteristics

Age (years), mean ± SD

57.6 ± 4.3

71.1 ± 4.1

85.1 ± 4.9

<0.0001

<0.0001

<0.0001

Male gender, N (%)

1377 (55.8)

1507 (57.6)

480 (64.2)

0.20

<0.0001

0.0012

APACHE II, mean ± SD

23.3 ± 9.1

26.5 ± 8.7

27.1 ± 8.0

<0.0001

<0.0001

0.11

Non-age APACHE II, mean ± SD

20.5 ± 9.0

21.2 ± 8.7

21.1 ± 8.0

0.02

0.14

0.75

Body mass index (Kg/m²), mean ± SD

29.1 ± 7.7

28.4 ± 8.0

27.1 ± 7.9

0.02

<0.0001

0.001

Functional status^‡ before admission,

N (%)

  No significant disability

801 (32.6)

395 (15.3)

61 (8.2)

<0.0001

<0.0001

<0.0001

  Slight disability

573 (23.4)

506 (19.5)

73 (9.8)

0.0006

<0.0001

<0.0001

  Moderate disability

429 (17.6)

691 (26.6)

691 (20.0)

<0.0001

0.13

0.0003

  Moderately severe disability

172 (7.0)

467 (18.0)

262 (35.2)

<0.0001

<0.0001

<0.0001

  Severe disability

91 (3.7)

233 (9.0)

117 (15.7)

<0.0001

<0.0001

<0.0001

Chronic illnesses, N (%)

  Cardiac

413 (16.9)

644 (24.8)

240 (32.2)

<0.0001

<0.0001

<0.0001

  Respiratory

328 (13.4)

475 (18.4)

162 (21.8)

<0.0001

<0.0001

0.04

  Renal

379 (15.5)

476 (18.4)

120 (16.2)

0.007

0.68

0.16

  Hepatic

511 (20.9)

354 (13.7)

46 (6.2)

<0.0001

<0.0001

<0.0001

  Immunocompromised

349 (14.3)

303 (11.7)

56 (7.5)

0.007

<0.0001

0.001

Main reason for ICU admission, N (%)

  Cardiovascular

452 (18.3)

655 (25)

231 (30.9)

<0.0001

<0.0001

0.0001

  Respiratory

862 (34.9)

1016 (38.8)

302 (40.4)

<0.0001

<0.0001

0.0001

  Neurological

175 (7.1)

181 (6.9)

60 (8.0)

<0.0001

<0.0001

0.0001

  Other medical

198 (8.0)

159 (6)

34 (4.6)

<0.0001

<0.0001

0.0001

  Non-operative trauma

84 (3.4)

47 (1.8)

7 (0.9)

<0.0001

<0.0001

0.0001

  Post operative

696 (28.2)

559 (21.4)

114 (15.3)

<0.0001

<0.0001

0.0001

Sepsis on admission, N (%)

723 (29.3)

723 (29.3)

838 (32)

0.04

0.06

0.65

Myocardial ischemia on admission, N (%)

227 (9.2)

367 (14.0)

151 (20.2)

<0.0001

<0.0001

<0.0001

Community-acquired pneumonia on admission, N (%)

207 (8.4)

348 (13.3)

99 (13.2)

<0.0001

<0.0001

0.96

Hospital-acquired pneumonia on admission, N (%)

83 (3.4)

95 (3.6)

33 (4.4)

0.61

0.18

0.32

New stroke on admission, N (%)

227 (9.2)

478 (18.2)

175 (23.4)

<0.0001

<0.0001

0.002

Admission GCS score, mean ± SD

10.5 ± 4.5

10.0 ± 4.5

9.2 ± 4.3

0.0002

<0.0001

<0.0001

Platelet count/μL, mean ± SD

212 ± 153

227 ± 153

243 ± 131

0.004

<0.0001

0.015

Lactate^¶ (mmol/L), mean ± SD

3.8 ± 4.0

3.7 ± 4.0

3.5 ± 3.8

0.66

0.12

0.20

Creatinine^¶ (μmol/L), mean ± SD

183 ± 175

190 ± 161

169 ± 130

0.18

0.052

0.005

Bilirubin* (μmol/L), mean ± SD

72 ± 138

44 ± 90

27 ± 61

<0.0001

<0.0001

0.0001

INR, mean ± SD

1.7 ± 1.1

1.7 ± 1.0

1.7 ± 1.1

0.66

0.6

0.88