Table 2 Baseline characteristics across stages of chronic kidney disease (CKD)

Age, years

78.6 (76.5–81.1)

79.6 (77.3–83.1)

81 (78.2–85.1)

81 (77.7–84.8)

< 0.001

Women, %

61.1

56.8

47.7

40.4

< 0.001

Living alone, %

23.1

23.7

26

32.6

ns

Education, years

12 (8–16)

11.5 (8–15)

10 (8–13)

8 (8–12)

< 0.001

 Current smoker, %

5.5

3.6

4.1

3.5

ns

 Former smoker, %

35.7

40

44.3

44.9

0.017

Alcohol ≥1 unit a day, %

26.6

24.2

27.2

24.8

ns

BMI, kg/m²

26.7 (24.2–29.6)

27.4 (24.8–30.6)

27.7 (25.3–31.0)

27.7 (24.9–31.4)

< 0.001

ADL-independent, %

97.1

95.7

92.1

90.1

< 0.001

iADL-independent, %

66

79.5

72.3

70.2

< 0.001

MMSE, score

29 (27–30)

29 (27–30)

29 (27–30)

30 (28–30)

0.001

 MMSE < 24, %

6.4

7.7

9.3

5

ns*

GDS, score

2 (1–4)

2 (1–4)

2 (1–4)

2 (1–4)

ns

 GDS > 5, %

13

15

14.1

14.2

ns

Hypertension, %

66.3

77.6

89.3

96.5

< 0.001

Diabetes mellitus, %

19.3

22.6

38.2

36.2

< 0.001

TIA, %

8

8.4

11.2

7.8

ns

Stroke, %

4.3

5.7

7.9

9.2

0.023

Atrial fibrillation, %

9.3

16.6

22

22.7

< 0.001

COPD, %

8.9

11.3

16.7

17.7

< 0.001

Cancer, %

14.2

17.2

20.8

24.8

0.002

CHF, %

8.4

17.9

23.9

34.8

< 0.001

Vascular disease, %

10.8

12.3

16.5

13.5

0.042

CIRS-G, total score

7 (4–10)

7 (5–10)

10 (7–14)

11.5 (8.3–15)

< 0.001

CIRS-G, severity index

1.4 (1.2–1.7)

1.5 (1.2–1.8)

1.7 (1.3–1.9)

1.8 (1.5–2)

< 0.001

eGFR-BIS, mL/min/1.73 m²

67.2 (63.6–73.1)

53.8 (50.2–56.9)

39.0 (34.9–42.3)

24 (20.5–27.1)

< 0.001

ACR, mg/g

8.3 (1.9–18.7)

9.4 (3.3–24.3)

24.5 (7–121.8)

161 (53.7–1006)

< 0.001

Albuminuria, %

14

20.8

45.6

81.6

< 0.001