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Table 1 Patient characteristics stratified by lactate level category

From: Prognostic impact of elevated lactate levels on mortality in critically ill patients with and without preadmission metformin treatment: a Danish registry-based cohort study

Characteristic

Total

< 1.4

1.4 to 2.0

2.0 to 3.2

3.2 to 5.0

5.0 to 10.0

≥ 10

No. of patients

37,293

14,572

8705

6831

3694

2544

947

Age, years

68 [56–77]

68 [57–77]

67 [55–77]

67 [53–77]

68 [55–77]

68 [56–77]

66 [55–74]

Male

21,244 (57)

8010 (55)

4971 (57)

3999 (59)

2125 (58)

1552 (61)

587 (62)

Charlson Comorbidity Index

 0

13,769 (37)

5122 (35)

3311 (38)

2667 (39)

1337 (36)

954 (38)

378 (40)

 1–2

14,005 (38)

5696 (39)

3248 (37)

2468 (36)

1344 (36)

931 (37)

318 (34)

 ≥ 3

9519 (26)

3754 (26)

2146 (25)

1696 (25)

1013 (27)

659 (26)

251 (27)

Preadmission disease

 Diabetes mellitus

7703 (21)

2790 (19)

1787 (21)

1404 (21)

812 (22)

673 (26)

237 (25)

 Myocardial infarction

2630 (7)

1108 (8)

621 (7)

425 (6)

251 (7)

162 (6)

63 (7)

 Congestive heart failure

3520 (9)

1424 (10)

837 (10)

594 (9)

341 (9)

236 (9)

88 (9)

 Peripheral vascular disease

4104 (11)

1648 (11)

998 (11)

681 (10)

400 (11)

278 (11)

99 (10)

 Cerebrovascular disease

5065 (14)

2084 (14)

1138 (13)

876 (13)

511 (14)

333 (13)

123 (13)

 Chronic pulmonary disease

6863 (18)

3011 (21)

1563 (18)

1151 (17)

642 (17)

387 (15)

109 (12)

 Cancer

6735 (18)

2771 (19)

1525 (18)

1238 (18)

683 (18)

401 (16)

117 (12)

 Mild-to-severe liver disease

1531 (4)

384 (3)

315 (4)

292 (4)

218 (6)

217 (9)

105 (11)

Renal function during 1 year before ICU admissiona

 eGFR, mL/min/1.73 m2

80 [59–95]

80 [58–95]

81 [61–95]

81 [59–96]

80 [59–96]

81 [59–96]

85 [62–99]

 ≥ 60 mL/min/1.73 m2

22,770 (74)

9029 (73)

5399 (76)

4041 (75)

2234 (74)

1506 (74)

561 (77)

 45–60 mL/min/1.73 m2

3773 (12)

1531 (12)

808 (11)

713 (13)

371 (12)

263 (13)

87 (12)

 30–45 mL/min/1.73 m2

2402 (8)

1020 (8)

528 (7)

398 (7)

242 (8)

162 (8)

52 (7)

 < 30 mL/min/1.73 m2

1641 (5)

755 (6)

352 (5)

244 (5)

163 (5)

98 (5)

29 (4)

 Dialysis before ICU admissionb

344 (1)

139 (1)

85 (1)

52 (1)

43 (1)

19 (1)

6 (1)

Antihyperglycemic therapy

 Metformin

3183 (9)

1047 (7)

758 (9)

596 (9)

353 (10)

300 (12)

129 (14)

 Sulfonylureas

899 (2)

309 (2)

233 (3)

150 (2)

104 (3)

72 (3)

31 (3)

 Insulin

2343 (6)

853 (6)

551 (6)

428 (6)

236 (6)

220 (9)

55 (6)

 Other antihyperglycemic agents

691 (2)

206 (1)

158 (2)

131 (2)

88 (2)

72 (3)

36 (4)

 HbA1c within 4 weeks before ICU admission,  %c

5.9 [5.5–6.7]

5.9 [5.5–6.5]

6.0 [5.5–6.7]

6.1 [5.5–7.0]

6.1 [5.5–6.9]

6.1 [5.5–7.0]

5.9 [5.5–7.0]

ICU admission typed

 Medical

17,926 (52)

5864 (43)

4033 (50)

3575 (56)

2188 (63)

1622 (68)

644 (73)

 Emergency surgery

10,683 (31)

4111 (30)

2506 (31)

2041 (32)

1078 (31)

722 (30)

225 (26)

 Elective surgery

6193 (18)

3623 (27)

1576 (19)

738 (12)

187 (5)

56 (2)

13 (1)

 SAPS-II scoree

40 [30–52]

35 [26–45]

38 [29–49]

41 [31–53]

47 [36–60]

54 [42–67]

62 [50–76]

Primary diagnostic category

 Cardiovascular

8466 (23)

3668 (25)

1931 (22)

1183 (17)

721 (20)

667 (26)

296 (31)

 Respiratory, incl. pneumonia

5244 (14)

2223 (15)

1251 (14)

972 (14)

498 (13)

248 (10)

52 (5)

 Infection or sepsis, excl. pneumonia

3425 (9)

1054 (7)

789 (9)

689 (10)

476 (13)

335 (13)

82 (9)

 Gastrointestinal and liver disease

4215 (11)

1635 (11)

923 (11)

783 (11)

435 (12)

313 (12)

126 (13)

 Neoplasms

3899 (10)

1777 (12)

971 (11)

713 (10)

282 (8)

125 (5)

31 (3)

 Trauma and poisoning

5014 (13)

1887 (13)

1247 (14)

1109 (16)

446 (12)

255 (10)

70 (7)

 Endocrinology

1013 (3)

381 (3)

203 (2)

226 (3)

93 (3)

79 (3)

31 (3)

 Other

6017 (16)

1947 (13)

1390 (16)

1156 (17)

743 (20)

522 (21)

259 (27)

Laboratory values 12 h before until 6 h after ICU admission

 First lactate, mmol/L

1.6 [1.0–3.0]

0.9 [0.7–1.2]

1.7 [1.4–2.0]

2.6 [2.1–3.3]

4.2 [3.4–5.5]

7.4 [5.6–9.6]

14.0 [11.4–17.0]

 Mean lactate, mmol/L

1.6 [1.1–2.8]

0.9 [0.8–1.1]

1.6 [1.5–1.8]

2.5 [2.3–2.8]

3.9 [3.5–4.4]

6.6 [5.7–7.9]

13.0 [11.3–15.8]

 Maximum lactate, mmol/L

2.1 [1.3–3.7]

1.1 [0.9–1.4]

2.0 [1.8–2.5]

3.2 [2.7–4.0]

5.1 [4.3–6.4]

8.8 [7.1–10.8]

15.3 [13.0–18.9]

 No. of lactate measurements

4 [2–6]

3 [2–5]

4 [2–6]

4 [2–6]

4 [2–6]

4 [2–7]

3 [1–7]

 Mean glucose, mmol/Lf

8.1 [6.7–10.1]

7.3 [6.3–8.6]

8.3 [7.0–9.9]

8.8 [7.1–10.9]

9.4 [7.4–12.1]

10.0 [7.4–13.6]

9.8 [6.8–14.1]

ICU treatment

 Mechanical ventilation

15,594 (42)

5377 (37)

3441 (40)

2839 (42)

1838 (50)

1466 (58)

633 (67)

 Inotropes or vasopressors

13,081 (35)

3712 (25)

2854 (33)

2641 (39)

1811 (49)

1461 (57)

602 (64)

 Renal replacement therapy

1919 (5)

440 (3)

316 (4)

351 (5)

291 (8)

331 (13)

190 (20)

 ICU length of stay, daysg

1.1 [0.7–2.8]

1.0 [0.7–2.1]

1.0 [0.7––2.8]

1.2 [0.6–3.3]

1.5 [0.7–4.0]

1.5 [0.6–4.3]

1.0 [0.4–3.3]

 Hospital length of stay, days

10 [5–20]

10 [6–20]

11 [6–21]

10 [5–21]

10 [4–21]

9 [3–21]

5 [1–15]

  1. Blood lactate level category based on quintiles and clinically relevant boundaries in mmol/L. Data are expressed as n (%) or median [IQR]
  2. aData missing for 6707 (18%) patients
  3. bAs per Danish regulation, frequencies smaller than five patients not being zero are not reported
  4. cData missing for 31,373 (84%) patients
  5. dData missing for 2491 (7%) patients
  6. eData missing for 25,932 (70%) patients
  7. fData missing for 807 (2%) patients
  8. gData missing for 2885 (8%) patients