Table 1 Clinicopathological findings of patients with ANCA-associated renal vasculitis in each anaemia severity group

Patient number

45

24

21

Gender male:female

20:25

12:12

8:13

Age (years)

71 ± 7.8 (47–82)

72 ± 7.0 (54–82)

70 ± 8.7 (47–82)

Birmingham vasculitis activity score

20 (12–39)

19 (12–36)

20 (12–39)

Haemoglobin on admission (g/dL)

9.0 ± 1.6

8.1 ± 1.1

10.1 ± 1.3

Minimum haemoglobin (g/dL)

7.5 ± 1.3

6.5 ± 0.6

8.7 ± 0.9

MCV (fL)

90 ± 6.2

88 ± 6.8

91 ± 5.1

MCH (pg)

29.5 ± 2.4

29.1 ± 2.6

30.0 ± 2.2

MCHC (%)

33.0 ± 1.2

32.9 ± 0.9

33.0 ± 1.3

Reticulocyte count (×10⁴/μL)

4.65 ± 2.50

4.23 ± 2.47

5.09 ± 2.54

Serum erythropoietin (mIU/mL)

15.1 (5.8–105)

17.5 (5.8–105)

14.5 (11–36.6)

Transferrin saturation (%)

14.7 (4.2–80.2)

12.8 (4.2–80.2)

17.5 (9.7–54.5)

Serum ferritin (ng/mL)

322 (46.9–2231)

382 (46.9–1839)

291 (94.9–2231)

Serum c-reactive protein (mg/dL)

6.8 (0.03–24.5)

7.9 (0.43–24.5)

5.0 (0.03–17.3)

Serum hepcidin-25 (ng/mL)

71.5 (10.5–463)

74.9 (45.9–463)

37 (10.5–363)

Serum albumin (g/dL)

2.6 ± 0.8

2.3 ± 0.6

2.9 ± 0.8

Serum creatinine on admission (mg/dL)

2.5 (1.0–10.8

2.9 (1.0–10.8)

2.3 (1.0–6.3)

Maximum serum creatinine (mg/dL)

3.2 (1.0–11.7)

4.4 (1.1–11.7)

2.4 (1.0–7.2)

eGFR on admission (mL/min/1.73 m²)

19.5 (4.2–54.2)

13.8 (4.2–44.6)

21.6 (7.0–54.2)

Minimum eGFR (mL/min/1.73 m²)

15.3 (3.9–54.2)

8.9 (3.9–39.2)

19.0 (4.8–54.2)

Blood urea nitrogen (mg/dL)

34.5 (13–101)

36.9 (13–101)

30.9 (18.3–62)

Serum cystatin c (mg/L)

2.8 ± 0.9

3.2 ± 0.9

2.2 ± 0.6

Number of renal biopsy, n (%)

33 (73)

13 (54)

20 (95)

Area of tubulointerstitial damage (%)

55 ± 21

65 ± 18

48 ± 20