Table 1 Baseline characteristic in all patients, and in relation to AKI recurrence risk

Age (years), median [IQR]

68.21 [56.52–77.70]

55.84 [49.02–69.52]

69.28 [58.07–78.23]

74.29 [64.72–79.16]

0.027

Gender (male)

68.9%

56.5%

71.0%

72.2%

0.848

Hypertension

47.7%

27.5%

50.8%

58.2%

0.248

Diabetes mellitus

18.3%

4.3%

22.6%

17.9%

0.380

COPD

14.8%

13.0%

14.3%

19.0%

0.313

CHF

6.4%

4.3%

7.1%

6.3%

0.804

Cancer

13.6%

10.1%

13.9%

15.2%

0.773

Immunosuppressive state

17.8%

11.6%

19.4%

17.7%

0.734

0.122

 Intra-abdominal

30.9%

29.0%

31.0%

32.9%

 Lung

37.3%

52.2%

33.3%

35.4%

 Endocarditis

0.5%

0.0%

0.0%

1.3%

 Line related

1.5%

1.4%

2.0%

0.0%

 Urinary tract

12.3%

8.7%

15.5%

6.3%

 Skin and soft infection

2.0%

0.0%

2.0%

3.8%

 Unknown/others

15.6%

8.7%

16.3%%

20.3%

Leukocytes, median [IQR]

13.60 [6.90–21.00]

12.6 [5.15–23.55]

13.60 [7.00–20.45]

15.50 [7.35–21.58]

0.441

Lactate (mg/dl), median [IQR]

23.0 [15.0–37.3]

[–]

26.0 [16.0–41.0]

26.0 [17.0–47.0]

0.437

Vasopresors

84.3%

83.8%

85.6%

79.7%

0.214

Septic shock

85.4%

85.5%

86.4%

82.3%

0.366

APACHE, median [IQR]

20 [16–25]

16 [12–19]

20 [16–27]

23 [19–27]

0.032

SOFA, median [IQR]

8 [6–10]

7 [5–8]

9 [7–11]

9 [6–11]

0.952

Mechanical ventilation

51.1%

54.4%

49.4%

51.9%

0.699

C-reactive protein (mg/l), median [IQR]

19.4 [10.30–27.50]

18.6 [7.85–25.45]

20.4 [10.7–29.20]

18.3 [11.05–27.55]

0.673

Procalcitonin (ng/l), median [IQR]

10.24 [2.54–30.37]

4.11 [1.25–10.91]

13.11 [3.31–34.00]

13.29 [2.32–41.90]

0.749

Baseline creatinine (mg/dl), median [IQR]

0.97 [0.80–1.13]

0.88 [0.72–1.00]

0.95 [0.80–1.15]

1.05 [0.90–1.20]

0.022

Baseline estimated GFR (ml/min/1.73 m²), median [IQR]

72.50 [58.36–87.86]

81.91 [64.79–102.55]

72.74 [57.23–86.47]

66.18 [53.84–77.55]

0.030

ICU stay (days), median [IQR]

4.99 [2.99–11.47]

4.99 [1.99–8.48]

3.98 [2.99–10.97]

9.97 [4.99–17.95]

<0.001

Hospital stay (days), median [IQR]

16.95 [10.22–30.92]

15.96 [10.97–32.41]

15.96 [9.97–28.92]

19.94 [13.96–34.90]

0.003

0.054

 1, n (%)

100 (24.7%)

–

79 (31.3%)

21 (26.6%)

 2, n (%)

121 (29.9%)

–

98 (38.9%)

23 (29.1%)

 3, n (%)

110 (27.2)

–

75 (29.8%)

35 (44.3%)

Maximal creatinine (mg/dl), median [IQR]

2.10 [1.40–3.16]

1.00 [0.84–1.10]

2.30 [1.70–3.19]

2.99 [2.10–4.00]

<0.001

Intra-hospital mortality, n (%)

104 (25.7%)

7 (10.1%)

60 (23.8%)

35 (44.3%)

<0.001

90-day mortality, n (%)

112 (27.7%)

8 (11.6%)

64 (25.4%)

38 (48.1%)

<0.001

End of follow-up mortality, n (%)

190 (46.9%)

22 (31.9%)

113 (44.8%)

53 (67.1%)

0.001