Table 1 Clinical characteristics at the time of biopsy by age

Male/female ratio

1:1

1.1/1

Age of disease onset

median: 69 (range: 19–87)

median: 37 (range: 1–64)

<0.001

Pre-biopsy follow-up (months)

median: 5 (range: 0–660)

median: 10 (range: 0–612)

<0.001

 <3 months

 > 3 months

165 (46.9%)

187 (53.1%)

848 (38.3%)

1366 (61.7%)

0.002

 nephrotic

 non-nephrotic

188 (55.6%)

134 (39.6%)

916 (42.8%)

1124 (52.5%)

<0.001

Hematuria

159 (45.3%)

1359 (61.8%)

<0.001

Nephrotic range proteinuria without hematuria

115 (34.2%)

453 (21.3%)

<0.001

Non-nephrotic proteinuria with hematuria

76 (22.5%)

787 (37%)

Nephrotic range proteinuria with hematuria

73 (21.6%)

461 (21.6%)

Non-nephrotic proteinuria without hematuria

58 (17.2%)

328 (15.4%)

Isolated hematuria

8 (2.4%)

72 (3.4%)

eGFR mL/min/1.73 m²

median 39.3 (range 2.5–161.6)

median 66.8 (range 2.7–252)

<0.001

eGFR ≥ 60 mL/min/1.73 m²

92 (26.1%)

1194 (53.9%)

<0.001

eGFR 30–59 mL/min/1.73 m²

113 (32.1%)

548 (24.8%)

eGFR 15–29 mL/min/1.73 m²

73 (20.7%)

238 (10.8%)

eGFR < 15 mL/min/1.73 m²

74 (21%)

234 (10.5%)

Duration of symptoms < 3 months

165 (46.9%)

847 (38.3%)

0.002

Duration of symptoms ≥3 months

187 (53.1%)

1367 (61.7%)

Hypertension

287 (84.2%)

1398 (67.1%)

<0.001

Diabetes

64 (18.5%)

160 (7.5%)

<0.001

Steroid treatment before the biopsy

59 (17.5%)

491 (23.7%)

0.012

Other immunosuppressive treatment during pre-biopsy follow-up

16 (4.8%)

187 (9.0%)

0.008