Table 1 Characteristics and outcomes of participants categorized by AG quartiles. Continuous variables were expressed as mean ± standard deviation (SD) and were compared between groups using the two-sample t-test. Categorical variables were presented as numbers (percentages) and were compared between groups using the chi-squared test.

From: Association between serum anion gap and all-cause mortality in critically ill patients with Gastrointestinal bleeding: insights from MIMIC-IV database

Features

Total (n = 2333)

Q1 (n = 574)

Q2 (n = 578)

Q3 (n = 590)

Q4 (n = 591)

P-value

Age, years

67.40 ± 15.97

65.32 ± 16.29

68.31 ± 15.58

69.56 ± 15.69

66.36 ± 16.01

< 0.001

Gender, n (%)

     

0.314

 Female

901 (38.62)

203 (35.37)

230 (39.79)

237 (40.17)

231 (39.09)

 

 Male

1432 (61.38)

371 (64.63)

348 (60.21)

353 (59.83)

360 (60.91)

 

Weight, kg

80.76 ± 21.96

80.35 ± 22.03

80.69 ± 21.77

80.97 ± 21.98

81.01 ± 22.10

0.952

WBC, K/µL

11.93 ± 10.08

9.86 ± 5.26

11.02 ± 8.20

12.23 ± 11.29

14.53 ± 13.04

< 0.001

RBC, m/µL

3.19 ± 0.62

3.14 ± 0.51

3.18 ± 0.59

3.22 ± 0.66

3.22 ± 0.71

0.070

Platelet, K/µL

180.97 ± 107.34

172.48 ± 92.66

184.06 ± 107.22

187.08 ± 109.66

180.09 ± 117.62

0.110

RDW, %

16.34 ± 2.49

16.02 ± 2.25

16.12 ± 2.31

16.41 ± 2.56

16.81 ± 2.74

< 0.001

Sodium, mmol/L

138.97 ± 4.83

139.47 ± 4.36

139.27 ± 4.25

138.76 ± 4.87

138.38 ± 5.63

< 0.001

Potassium, mmol/L

4.20 ± 0.59

4.09 ± 0.51

4.12 ± 0.54

4.22 ± 0.56

4.36 ± 0.68

< 0.001

Calcium, mg/dL

8.14 ± 0.71

7.90 ± 0.61

8.12 ± 0.63

8.26 ± 0.67

8.27 ± 0.84

< 0.001

Glucose, mg/dL

138.00 ± 51.16

127.59 ± 42.91

133.44 ± 43.98

140.03 ± 52.04

150.52 ± 60.61

< 0.001

AG, mmol/L

14.47 ± 3.90

10.20 ± 1.19

12.74 ± 0.57

15.02 ± 0.77

19.75 ± 3.00

< 0.001

PTT, sec

36.99 ± 16.33

33.72 ± 13.08

34.65 ± 13.96

37.46 ± 18.17

41.97 ± 18.07

< 0.001

Urea nitrogen, mg/dL

35.96 ± 27.05

24.63 ± 14.70

29.38 ± 18.75

36.46 ± 25.90

52.91 ± 34.85

< 0.001

Creatinine, mg/dL

1.57 ± 1.47

0.88 ± 0.36

1.11 ± 0.67

1.49 ± 1.02

2.78 ± 2.19

< 0.001

Phosphate, mg/dL

3.64 ± 1.29

3.12 ± 0.77

3.31 ± 0.86

3.61 ± 0.99

4.52 ± 1.77

< 0.001

SOFA

5.63 ± 4.08

4.25 ± 3.27

4.56 ± 3.36

5.49 ± 3.76

8.18 ± 4.55

< 0.001

APS III

49.56 ± 20.80

42.15 ± 15.64

43.92 ± 17.41

48.98 ± 18.23

62.84 ± 24.12

< 0.001

SAPS II

38.65 ± 14.19

33.25 ± 12.05

35.39 ± 12.18

39.18 ± 12.78

46.55 ± 15.65

< 0.001

OASIS

32.13 ± 8.68

30.33 ± 8.21

30.72 ± 7.84

31.78 ± 7.87

35.59 ± 9.65

< 0.001

SIRS

2.61 ± 0.93

2.45 ± 0.94

2.58 ± 0.92

2.54 ± 0.93

2.84 ± 0.90

< 0.001

SBP, mmHg

119.45 ± 113.16

116.53 ± 14.45

126.93 ± 225.57

118.89 ± 17.27

115.53 ± 16.54

0.304

DBP, mmHg

64.79 ± 78.82

63.10 ± 9.54

69.82 ± 156.95

63.11 ± 14.02

63.20 ± 12.15

0.373

MBP, mmHg

76.23 ± 10.79

76.28 ± 9.46

76.14 ± 10.32

76.54 ± 11.72

75.95 ± 11.47

0.820

Length of hospital stay, days

12.96 ± 14.38

10.25 ± 11.28

12.12 ± 14.02

14.01 ± 15.27

15.36 ± 15.94

< 0.001

Length of ICU stay, days

4.44 ± 5.64

3.62 ± 4.73

3.78 ± 5.04

4.76 ± 6.29

5.56 ± 6.11

< 0.001

Hypertension, n (%)

     

< 0.001

 No

1421 (60.91)

328 (57.14)

330 (57.09)

358 (60.68)

405 (68.53)

 

 Yes

912 (39.09)

246 (42.86)

248 (42.91)

232 (39.32)

186 (31.47)

 

Diabetes, n (%)

     

< 0.001

 No

1639 (70.25)

441 (76.83)

409 (70.76)

396 (67.12)

393 (66.50)

 

 Yes

694 (29.75)

133 (23.17)

169 (29.24)

194 (32.88)

198 (33.50)

 

Heart failure, n (%)

     

< 0.001

 No

1705 (73.08)

479 (83.45)

436 (75.43)

404 (68.47)

386 (65.31)

 

 Yes

628 (26.92)

95 (16.55)

142 (24.57)

186 (31.53)

205 (34.69)

 

CKD, n (%)

     

< 0.001

 No

1817 (77.88)

507 (88.33)

468 (80.97)

425 (72.03)

417 (70.56)

 

 Yes

516 (22.12)

67 (11.67)

110 (19.03)

165 (27.97)

174 (29.44)

 

Stroke, n (%)

     

0.721

 No

2165 (92.80)

537 (93.55)

538 (93.08)

542 (91.86)

548 (92.72)

 

 Yes

168 (7.20)

37 (6.45)

40 (6.92)

48 (8.14)

43 (7.28)

 

COPD, n(%)

     

0.006

 No

2170 (93.01)

543 (94.60)

548 (94.81)

546 (92.54)

533 (90.19)

 

 Yes

163 (6.99)

31 (5.40)

30 (5.19)

44 (7.46)

58 (9.81)

 

MV, n (%)

     

< 0.001

 No

584 (25.03)

173 (30.14)

176 (30.45)

140 (23.73)

95 (16.07)

 

 Yes

1749 (74.97)

401 (69.86)

402 (69.55)

450 (76.27)

496 (83.93)

 

Enteral nutrition, n (%)

     

0.372

 No

2270 (97.30)

558 (97.21)

567 (98.10)

569 (96.44)

576 (97.46)

 

 Yes

63 (2.70)

16 (2.79)

11 (1.90)

21 (3.56)

15 (2.54)

 

Proton pump inhibitor, n (%)

     

0.050

 No

463 (19.80)

105 (18.30)

126 (21.80)

132 (22.40)

100 (16.90)

 

 Yes

1870 (80.20)

469 (81.70)

452 (78.20)

458 (77.60)

491 (83.10)

 

Anticoagulant, n (%)

     

< 0.001

 No

1778 (76.20)

480 (83.60)

443 (76.60)

420 (71.20)

435 (73.60)

 

 Yes

555 (23.80)

94 (16.40)

135 (23.40)

170 (28.80)

156 (26.40)

 

Blood transfusion, n (%)

     

< 0.001

 No

1500 (64.30)

388 (67.60)

377 (65.20)

399 (67.60)

336 (56.90)

 

 Yes

833 (35.70)

186 (32.40)

201 (34.80)

191 (32.40)

255 (43.10)

 

Vasopressor drug, n (%)

     

< 0.001

 No

2104 (90.20)

543 (94.60)

543 (93.90)

541 (91.70)

477 (80.70)

 

 Yes

229 (9.80)

31 (5.40)

35 (6.10)

49 (8.30)

114 (19.30)

 

Hospital-mortality, n (%)

     

< 0.001

 No

1998 (85.64)

535 (93.21)

523 (90.48)

516 (87.46)

424 (71.74)

 

 Yes

335 (14.36)

39 (6.79)

55 (9.52)

74 (12.54)

167 (28.26)

 

ICU-mortality, n (%)

     

< 0.001

 No

2119 (90.83)

553 (96.34)

550 (95.16)

545 (92.37)

471 (79.70)

 

 Yes

214 (9.17)

21 (3.66)

28 (4.84)

45 (7.63)

120 (20.30)

 

90-day mortality, n (%)

     

< 0.001

 No

1686 (72.27)

480 (83.62)

450 (77.85)

429 (72.71)

327 (55.33)

 

 Yes

647 (27.73)

94 (16.38)

128 (22.15)

161 (27.29)

264 (44.67)