Table 1 Baseline characteristics of the two groups stratified by median pre-CRRT 6-h urine output before and after propensity score matching at the time of CRRT initiation

Age (years)

75.1 (69.7–80.0)

74.0 (70.0–80.0)

0.80

−0.02

76.0 (70.2–80.6)

73.5 (69.5–80.0)

0.5

0.04

Sex, male (n (%))

180 (59.4 %)

185 (60.9 %)

0.74

−0.01

145 (60.2 %)

145 (60.2 %)

1.00

0.03

Body mass index (kg/m²)

23.1 (20.1–25.8)

22.5 (20.0–25.0)

0.64

23.0 (20.2–25.6)

22.2 (19.7–25.0)

0.61

Cause of acute kidney injury (n (%))

0.37

0.28

 Septic

138 (45.5 %)

137 (45.1 %)

116 (48.1 %)

116 (48.1 %)

 Nephrotoxic

27 (8.9 %)

18 (5.9 %)

20 (8.3 %)

12 (5.0 %)

 Ischemic

49 (16.2 %)

63 (20.7 %)

37 (15.4 %)

46 (19.1 %)

 Postoperative

34 (11.2 %)

25 (8.2 %)

26 (10.8 %)

21 (8.7 %)

 Others

55 (18.2 %)

61 (20.1 %)

42 (17.4 %)

46 (19.1 %)

Time from ICU admission to CRRT initiation (h)

6.8 (1.5–31.1)

7.9 (1.7–37.8)

0.30

7.0 (1.6–32.0)

7.7 (1.6–32.1)

0.95

Charlson comorbidity index

7.0 (4.0–11.0)

5.0 (4.0–8.0)

0.23

−0.05

7.0 (4.0–11.0)

5.0 (4.0–8.0)

0.70

0.02

SOFA score

11.6 ± 3.7

12.5 ± 3.4

0.08

11.8 ± 3.6

12.4 ± 3.4

0.11

APACHE II score

28.5 ± 7.4

29.6 ± 7.1

0.19

29.2 ± 7.4

29.5 ± 7.1

0.65

Mechanical ventilation needs (n (%))

251 (82.8 %)

253 (83.5 %)

0.78

203 (84.2 %)

200 (83.0 %)

0.60

 FiO₂

0.5 (0.4–0.5)

0.5 (0.4–0.5)

0.76

0.5 (0.4–0.5)

0.5 (0.4–0.5)

0.71

Systolic blood pressure (mmHg)

115.1 ± 24.7

109.3 ± 24.8

<0.01

0.31

111.9 ± 22.0

109.7 ± 24.7

0.30

0.08

Diastolic blood pressure (mmHg)

61.8 ± 14.0

61.0 ± 15.0

0.48

61.2 ± 13.1

61.8 ± 15.1

0.63

Mean arterial pressure (mmHg)

79.6 ± 15.6

77.1 ± 16.3

0.05

78.1 ± 14.1

77.8 ± 16.3

0.82

Six-hour urine volume before CRRT initiation (mL)

230.0 (150.0–432.0)

20.0 (0.0–40.0)

<0.01

220.0 (147.5–420.0)

23.0 (0.0–43.8)

<0.01

Cumulative fluid balance (mL)

1951.0 (424.8–3435.5)

2025.0 (0.0–4520.0)

0.06

1961.0 (544.5–3635.5)

2072.7 (0.0–4655.0)

0.37

Diuretics use (n (%))

209 (69.0 %)

194 (63.8 %)

0.20

164 (68.0 %)

148 (61.4 %)

0.15

Target clearance (mL/kg/h)

40.0 (38.1–50.0)

40.0 (36.7–47.1)

0.88

40.0 (38.4–49.5)

40.0 (37.2–46.6)

0.70

Dialysate flow rate (mL/h)

1250.0 (1000.0–1550.0)

1100.0 (1000.0–1500.0)

0.23

1200.0 (1000.0–1500.0)

1100.0 (1000.0–1475.0)

0.34

Replacement flow rate (mL/h)

1200.0 (1000.0–1500.0)

1100.0 (1000.0–1500.0)

0.13

1200.0 (1000.0–1500.0)

1100.0 (1000.0–1475.0)

0.17

Blood flow rate (mL/min)

100.0 (100.0–100.0)

100.0 (100.0–100.0)

0.70

100.0 (100.0–100.0)

100.0 (100.0–100.0)

0.38

Biochemical data

 White blood cells (n/μL)

12370.0 (7600.0–20500.0)

12975.0 (8495.0–24542.5)

0.11

12370.0 (7370.0–20570.0)

12975.0 (8500.0–24522.5)

0.06

 Hemoglobin (g/dL)

9.7 (8.6–11.3)

9.4 (8.0–11.2)

0.38

9.8 (8.6–11.4)

9.4 (8.0–11.4)

0.76

 Platelets (×10³/μL)

104.0 (59.0–161.0)

96.0 (60.0–167.5)

0.42

98.0 (57.5–159.0)

96.0 (60.0–169.0)

0.68

 PT-INR

1.4 (1.2–1.9)

1.7 (1.4–2.6)

<0.01

−0.74

1.5 (1.2–2.0)

1.7 (1.3–2.4)

0.16

−0.22

 Albumin (g/dL)

2.7 ± 0.5

2.7 ± 0.6

0.96

2.6 ± 0.5

2.7 ± 0.6

0.35

 Total bilirubin (mg/dL)

1.1 (0.8–.0)

1.6 (0.8–3.9)

<0.01

−0.43

1.2 (0.8–2.2)

1.5 (0.8–3.3)

0.18

−0.08

 Aspartate aminotransferase (IU/L)

68.0 (36.0–212.0)

198.5 (52.0–1049.8)

<0.01

73.0 (36.0–254.5)

168.0 (47.3–1020.8)

<0.01

 Alanine aminotransferase (IU/L)

27.0 (16.0–117.0)

82.0 (19.0–379.0)

<0.01

28.0 (16.0–126.5)

75.5 (19.0–347.5)

<0.01

 Blood urea nitrogen (mg/dL)

49.0 (35.0–71.0)

43.0 (32.0–65.5)

0.61

49.0 (33.0–69.0)

43.5 (32.0–63.5)

0.54

 Creatinine (mg/dL)

2.8 (2.0–3.7)

2.7 (2.0–4.0)

0.07

2.7 (2.0–3.4)

2.7 (2.0–4.0)

0.01