Table 2 Comparisons of baseline characteristics and outcomes between patients with persistent and transient AKI.

Age (years), mean (SD)

63.3 ± 16.9

63.2 ± 17

63.5 ± 16.7

0.793

Male, n (%)

628 (65.8)

381 (65.8)

247 (65.7)

1

Smoking, n (%)

384 (40.2)

233 (40.2)

151 (40.2)

1

Alcohol drinking, n (%)

375 (39.3)

233 (40.2)

142 (37.8)

0.485

SOFA (score), mean (SD)

6.9 ± 3.4

6.4 ± 3.2

7.8 ± 3.6

 < 0.001

APACHE II (score), mean (SD)

19.3 ± 7.2

18.6 ± 6.7

20.3 ± 7.8

 < 0.001

Surgery time (hours), mean (SD)

3.1 ± 2.3

3 ± 2

3.2 ± 2.6

0.276

Surgery, n (%)

 < 0.001

Abdominal

242 (25.3)

169 (29.2)

73 (19.4)

Cerebral

172 (18)

84 (14.5)

88 (23.4)

Orthopaedic

240 (25.1)

143 (24.7)

97 (25.8)

Cardiothoracic

105 (11)

81 (14)

24 (6.4)

Others

196 (20.5)

102 (17.6)

94 (25)

Contrast agent use, n (%)

624 (65.3)

361 (62.3)

263 (69.9)

0.019

Antibiotic use, n (%)

43 (4.5)

14 (2.4)

29 (7.7)

 < 0.001

Diuretic use, n (%)

778 (81.5)

445 (76.9)

333 (88.6)

 < 0.001

AKI stage

 < 0.001

1

588 (61.6)

424 (73.7)

161 (42.8)

2

229 (24)

124 (21.4)

105 (27.9)

3

138 (14.5)

28 (4.8)

110 (29.3)

Uo_6h (mL), mean (SD)

324.8 ± 455.5

239.2 ± 400.5

456.7 ± 501.9

 < 0.001

Uo_24h (mL), median (IQR)

1735 (1100, 2400)

1700 (1150, 2350)

1787.5 (1000, 2556.25)

0.792

Comorbidities, n (%)

Hypertension

429 (44.9)

245 (42.3)

184 (48.9)

0.052

Diabetes

125 (13.1)

56 (9.7)

69 (18.4)

 < 0.001

Myocardial infarction, n (%)

87 (9.1)

32 (5.5)

55 (14.6)

 < 0.001

Chronic obstructive pulmonary disease

74 (7.7)

45 (7.8)

29 (7.7)

1

Solid tumour

110 (11.5)

79 (13.6)

31 (8.2)

0.014

Sepsis

550 (57.6)

337 (58.2)

213 (56.6)

0.683

Biochemical indexes on ICU admission, mean (SD)

Creatinine (mmol/L)

106 ± 59.9

83.4 ± 32.4

140.8 ± 74.2

 < 0.001

Urea (mmol/L)

9.2 ± 4.6

8.1 ± 3.5

10.9 ± 5.5

 < 0.001

White blood cell (× 10⁹/L)

12.5 ± 6.6

12 ± 6

13.1 ± 7.4

0.016

Red blood cell (× 10⁹/L)

3.6 ± 0.8

3.6 ± 0.7

3.5 ± 0.9

0.024

Platelet count (× 10⁹/L)

151.4 ± 78.2

157.5 ± 79.8

142 ± 74.7

0.002

pH

7.4 ± 0.1

7.4 ± 0.1

7.3 ± 0.1

 < 0.001

Bicarbonate (mmol/L)

20.9 ± 3.8

21.6 ± 3.1

19.7 ± 4.4

 < 0.001

Lactate (mmol/L)

3.4 ± 3.2

2.7 ± 2.3

4.4 ± 4.1

 < 0.001

Prothrombin time (s)

16.4 ± 6.2

15.6 ± 2.7

17.7 ± 9.2

 < 0.001

Potassium (mmol/L)

4.2 ± 0.7

4.1 ± 0.6

4.3 ± 0.8

0.012

Sodium (mmol/L)

141.1 ± 4.9

140.7 ± 4.5

141.8 ± 5.5

0.002

Vital signs on first day ICU admission, mean (SD)

Minimum glucose (mmol/L)

6.6 ± 1.8

6.5 ± 1.6

6.9 ± 2

0.006

Maximum glucose (mmol/l)

11.6 ± 4.9

10.8 ± 3.6

13 ± 6.3

 < 0.001

Mean glucose (mmol/l)

8.9 ± 2.4

8.4 ± 2

9.6 ± 2.9

 < 0.001

Minimum systolic pressure (mmHg)

92.9 ± 19.7

96.3 ± 19.1

87.8 ± 19.6

 < 0.001

Maximum systolic pressure (mmHg)

179.2 ± 126.9

186.9 ± 151

167.4 ± 75

0.008

Mean systolic pressure (mmHg)

125.3 ± 16.9

127.8 ± 16.6

121.4 ± 16.8

 < 0.001

Minimum diastolic pressure (mmHg)

49.9 ± 10.1

51.2 ± 9.8

47.9 ± 10.2

 < 0.001

Maximum diastolic pressure (mmHg)

91.8 ± 43.5

90.4 ± 34.6

94 ± 54.4

0.244

Mean diastolic pressure (mmHg)

66.6 ± 9.8

67.1 ± 9.6

65.9 ± 10.1

0.088

Mean temperature (°C)

37.2 ± 0.7

37.2 ± 0.6

37.1 ± 0.8

 < 0.001

Minimum temperature (°C)

36.1 ± 0.9

36.2 ± 0.8

35.9 ± 1.1

 < 0.001

Maximum temperature (°C)

38.1 ± 0.8

38.1 ± 0.7

38 ± 0.9

0.552

Mean heart rate (bpm)

89.8 ± 19

86.5 ± 17

94.9 ± 20.7

 < 0.001

Minimum heart rate (bpm)

69.6 ± 18.2

67.5 ± 15.9

72.8 ± 20.9

 < 0.001

Maximum heart rate (bpm)

115.8 ± 27.2

111.7 ± 25.7

122 ± 28.2

 < 0.001

Clinical outcomes

ICU length of stay (days), median (IQR)

5.97 (3.67, 12.67)

5.23 (3.12, 11.63)

7.36 (4.51, 13.92)

 < 0.001

Ventilation duration (days), median (IQR)

2.16 (0.7, 8.44)

1.65 (0.56, 7.74)

3.32 (0.81, 9.38)

0.002

Hosp. LOS (days), median (IQR)

22 (14, 33)

22 (14.5, 33)

22 (13, 33)

0.497

Cost (× 10³ yuan)

71.63 (46.73, 108.8)

64.18 (44.23, 94.55)

83.16 (52.1, 139.01)

 < 0.001

Hospital mortality, n (%)

171 (17.9)

57 (9.8)

114 (30.3)

 < 0.001