Table 1 Baseline characteristics of the cohort according to renal disease status

 Age in years, mean (SD)

60.2 (19.3)

59.3 (19.6)

67.9 (14.2)

<0.001

61.1 (14.3)

<0.001

71.1 (13.6)

<0.001

70.4 (11.4)

<0.001

 Age in years, median (IQR)

64 (47–76)

63 (45–75)

70 (61–78)

63 (52–72)

63 (52–72)

72 (64–81)

 Length of ICU stay (hours), median (IQR)

24 (13–60)

23 (12–53)

68 (26–189)

<0.001

26 (15–58)

<0.001

27 (15–63)

<0.001

64 (25–156)

<0.001

 Women, n (%)

44,480 (43.0)

40,411 (43.6)

2086 (39.6)

<0.001

500 (36.0)

<0.001

1140 (35.7)

<0.001

343 (34.4)

<0.001

 Admissions per patient, mean (SD)

1.3 (0.88)

1.31 (0.89)

1.29 (0.74)

0.19

1.36 (0.86)

<0.001

1.35 (0.88)

0.005

1.30 (0.74)

0.55

 Admissions per patient, median (IQR)

1 (1–1)

1 (1–1)

1 (1–1)

1 (1–1)

1 (1–1)

1 (1–1)

 Highest potassium (mmol/l)

4.2 (3.9–4.6)

4.1 (3.9–4.5)

4.7 (4.1–5.5)

<0.001

4.8 (4.2–5.5)

<0.001

4.4 (4.0–5.0)

<0.001

4.9 (4.3–5.7)

<0.001

 n

18,743

16,069

1605

273

534

262

 Highest sodium (mmol/l)

139 (136–142)

139 (136–142)

137 (134–141)

<0.001

138 (135–140)

<0.001

139 (136–142)

0.65

138 (135–141)

<0.001

 n

18,792

16,121

279

270

535

262

 Lowest sodium (mmol/l)

136 (133–139)

136 (133–139)

133 (130–137)

<0.001

134 (132–137)

136 (133–140)

134 (130–137)

 n

18,797

16,121

1604

 Highest bilirubin (μmol/l)

10 (6–18)

10 (6–17)

14 (8–26)

<0.001

10 (6–17)

0.92

10 (7–17)

0.42

12(7–22)

<0.001

 n

19,797

16,863

1768

207

633

326

 Lowest arterial pH

7.36 (7.29–7.41)

7.36 (7.30–7.41)

7.29 (7.19–7.38)

<0.001

7.35 (7.2–7.4)

<0.001

7.34 (7.25–7.4)

<0.001

7.28 (7.17–7.36)

<0.001

 n

47,318

40,449

3968

598

1586

717

 Lowest bicarbonate (mmol/l)

22 (19–25)

23 (20–25)

18 (14–22)

<0.001

23 (19–24)

0.213

21 (18–25)

0.002

19(14–21)

<0.001

 n

4566

3662

593

62

134

115

 Maximum creatinine (μmol/l)

85 (65–125)

80 (63–105)

254 (164–422)

<0.001

460 (275–673)

<0.001

185 (129–277)

<0.001

363 (238–553)

<0.001

 n

54,655

47,441

4076

660

1738

740

 Maximum urea (mmol/l)

8 (4.9–14.3)

6.7 (4.3–10.1)

17.5 (11–26)

<0.001

19.4 (15–25)

<0.001

16.6 (11.9–24.5)

<0.001

27 (19.3–36.6)

<0.001

 n

3519

2717

532

62

104

104

 Lowest thrombocyte count (× 10⁹/l)

228 (166–296)

230 (170–296)

199 (123–291)

<0.001

217 (153–286)

0.003

220 (152–292)

<0.001

203 (131–277)

<0.001

 n

37,438

32,586

2695

421

1217

519

 APACHE II score

15 (9–22)

14 (8–20)

25 (20–32)

<0.001

22 (17–28)

<0.001

19 (14–26)

<0.001

27 (21–33)

<0.001

 n

19,962

17,231

1620

284

564

263

 SAPS-II score

27 (0–44)

25 (0–41)

55 (42–70)

<0.001

35 (16–52)

<0.001

40 (23–53)

<0.001

56 (43–68)

<0.001

 n

17,074

15,376

764

269

503

162

 SAPS-III score

54 (44–65)

52 (43–63)

68 (59–77)

<0.001

60 (51–71)

<0.001

64 (55–72)

<0.001

69 (60–78)

<0.001

 n

20,970

18,326

1437

195

736

276

 Invasive mechanical ventilation, n (%)

8621 (8.3)

7155 (7.7)

994 (18.9)

<0.001

93 (6.7)

0.156

201 (6.3)

0.002

178 (17.8)

<0.001

 Acute surgery, n (%)

8379 (8.1)

7282 (7.8)

662 (12.6)

<0.001

109 (7.8)

1.0

228 (7.14)

0.132

98 (9.82)

0.029

 Elective surgery, n (%)

5889 (5.7)

5237 (5.7)

295 (5.6)

1.0

83 (6.0)

0.6

201 (6.3)

0.111

69 (6.9)

0.098

 Charlson comorbidity score, mean^c (SD)

2,03 (2.42)

1.8 (2.2)

2.6 (2.5)

<0.001

5.2 (2.5)

<0.001

5.8 (2.6)

<0.001

5.6 (2.6)

<0.001

 Charlson score with renal points removed, mean (SD)

1.92 (2.3)

1.78 (2.2)

2.6 (2.5)

<0.001

3.2 (2.4)

<0.001

3.8 (2.6)

<0.001

3.6 (2.6)

<0.001

 Myocardial infarction, n (%)

14,605 (14.1)

11,896 (12.9)

986 (18)

<0.001

387 (28.0)

<0.001

1047 (32.8)

<0.001

289 (29.0)

<0.001

 Congestive cardiac failure, n (%)

16,281 (15.7)

12,521 (13.5)

1324 (25.1)

<0.001

438 (31.5)

<0.001

1563 (48.9)

<0.001

435 (43.6)

<0.001

 Peripheral vascular disease, n (%)

10,948 (10.6)

8921 (9.6)

704 (13.4)

<0.001

348 (25.0)

<0.001

761 (23.8)

<0.001

214 (21.4)

<0.001

 Cerebrovascular disease, n (%)

17,742 (17.2)

15,658 (16.9)

808 (15.3)

<0.001

310 (22.3)

<0.001

789 (24.7)

<0.001

177 (17.7)

0.497

 Dementia, n (%)

2070 (2.0)

1840 (2.0)

99 (1.9)

0.612

16 (1.2)

0.03

100 (3.13)

<0.001

15 (1.50)

0.359

 COPD, n (%)

14,841 (14.4)

12,999 (14.1)

808 (15.3)

0.010

150 (10.8)

<0.001

696 (21.8)

<0.001

188 (18.8)

<0.001

 Rheumatological disease, n (%)

4006 (3.8)

3311 (3.6)

269 (5.1)

<0.001

93 (6.7)

<0.001

262 (8.2)

<0.001

71 (7.1)

<0.001

 Peptic ulcer disease, n (%)

6729 (6.5)

5693 (6.2)

423(8.0)

<0.001

154 (11.2)

<0.001

362 (11.3)

<0.001

97 (9.7)

<0.001

 Cancer, n (%)

18,175 (17.6)

15,726 (17.0)

1262 (24.0)

<0.001

217 (15.7)

0.183

738 (23.1)

<0.001

232 (23.3)

<0.001

 Metastatic disease, n (%)

3747 (3.6)

1918 (3.6)

304 (4.7)

<0.001

24 (1.7)

<0.001

127 (4.0)

0.246

28 (2.8)

0.199

 Mild liver disease, n (%)

5272 (5.1)

4504 (4.9)

369 (7.0)

<0.001

123 (8.9)

<0.001

210 (6.6)

<0.001

66 (6.6)

0.015

 Moderate or severe liver disease, n (%)

2436 (2.4)

3319 (2.1)

249 (5.8)

<0.001

31 (2.2)

0.64

125 (3.9)

<0.001

58 (5.8)

<0.001

 Uncomplicated diabetes, n (%)

16,684 (16.1)

13,168 (14.2)

1372 (26.2)

<0.001

537 (38.7)

<0.001

1215 (38.0)

<0.001

392 (39.3)

<0.001

 Diabetes with complications, n (%)

6756 (6.5)

4660 (5.0)

523 (9.9)

<0.001

499 (35.9)

<0.001

806 (25.2)

<0.001

268 (26.9)

<0.001

 Paraplegia, n (%)

2004 (1.9)

1787 (1.9)

90 (1.7)

0.287

29 (2.07)

0.624

78 (2.44)

0.043

20 (2.00

0.817

 HIV, n (%)

137 (0.13)

125 (0.14)

4 (0.08)

0.328

3 (0.22)

0.44

5 (0.16)

0.63

0 (0)

0.65