Table 1.
Baseline characteristics of the validation cohort according to histopathologic class
| Baseline Characteristics | Focal, n=52 | Crescentic, n=37 | Mixed, n=39 | Sclerotic, n=17 |
|---|---|---|---|---|
| Age at biopsy, yr, mean ± SD | 60±13 | 62±11 | 61±14 | 66±12 |
| Men (%) | 33 (64) | 24 (65) | 18 (46) | 8 (47) |
| Diagnosis (%)a | ||||
| Granulomatosis with polyangiitis | 33 (63) | 14 (40) | 8 (21) | 8 (50) |
| Microscopic polyangiitis | 17 (33) | 19 (54) | 27 (73) | 8 (50) |
| Eosinophilic granulomatosis with polyangiitis | 1 (2) | 0 (0.0) | 1 (3) | 0 (0) |
| Kidney limited vasculitis | 1 (2) | 2 (6) | 1 (3) | 0 (0) |
| ANCA specificity (%)b | ||||
| PR3 | 23 (48) | 13 (37) | 7 (20) | 7 (44) |
| MPO | 19 (40) | 21 (60) | 25 (69) | 8 (50) |
| Negative | 3 (6) | 0 (0) | 3 (8) | 0 (0) |
| Double positive | 3 (6) | 1 (3) | 1 (3) | 1 (6) |
| Diagnostic delay, mo, mean ± SD | 4.7±12.9 | 1.4±2.7 | 2.4±3.2 | 3.6±11.5 |
| eGFR0, ml/min per 1.73 m2, mean ± SD | 50±29 | 18±16 | 27±19 | 19±12 |
| Proteinuria class at biopsy (%)c | ||||
| Normal | 4 (9) | 1 (3) | 2 (5) | 0 (0) |
| Moderately increased | 18 (39) | 4 (13) | 3 (8) | 3 (19) |
| Severely increased | 24 (52) | 27 (84) | 33 (87) | 13 (81) |
PR3, proteinase-3; MPO, myeloperoxidase.
a
The diagnosis was specified in 140 patients.
b
ELISA test results were available in 135 patients.
c
In accordance with the Kidney Disease Improving Global Outcomes clinical guidelines, normal level of proteinuria was defined as protein excretion of <0.15 g/d or as a negative protein dipstick test, moderately increased proteinuria was defined as a protein excretion rate of 0.15–0.50 g/d or as trace on protein dipstick test, and severely increased proteinuria was defined as total protein excretion >0.50 g/d or as + or more on protein dipstick. The proteinuria class could be determined in 132 patients.