Demographic and disease features of cases of MPA and comparators*
| MPA (n=291) | Comparators (n=822)* | P value | |
| Age, mean±SD years | 65.5±13.2 | 52.0±16.9 | <0.001 |
| Sex, no. (%) female | 164 (56.4) | 394 (47.9) | 0.016 |
| Maximum serum creatinine, mean | <0.001 | ||
| μmoles/L | 126.4 | 185.2 | |
| mg/dL | 1.4 | 2.1 | |
| cANCA positive, no. (%) | 11 (3.8) | 257 (31.3) | <0.001 |
| pANCA positive, no. (%) | 236 (81.1) | 136 (16.5) | <0.001 |
| Anti-PR3-ANCA positive, no. (%) | 6 (2.1) | 265 (32.2) | <0.001 |
| Anti-MPO-ANCA positive, no. (%) | 279 (95.9) | 142 (17.3) | <0.001 |
| Maximum eosinophil count ≥1×109/L, no. (%) | 15 (5.2) | 244 (29.7) | <0.001 |
*Diagnoses of comparators for the classification criteria for microscopic polyangiitis (MPA) included granulomatosis with polyangiitis (n=300), eosinophilic granulomatosis with polyangiitis (n=226), polyarteritis nodosa (n=51), non-ANCA-associated small-vessel vasculitis that could not be subtyped (n=51), Behçet’s disease (n=50), IgA vasculitis (n=50), cryoglobulinaemic vasculitis (n=34), ANCA-associated vasculitis that could not be subtyped (n=25), primary central nervous system vasculitis (n=19) and anti-glomerular basement membrane disease (n=16).
ANCA, antineutrophil cytoplasmic antibody; anti-MPO-ANCA, anti-myeloperoxidase-ANCA; anti-PR3-ANCA, anti-proteinase 3-ANCA; cANCA, cytoplasmic antineutrophil cytoplasmic antibody; pANCA, perinuclear ANCA.