Baseline characteristics of the 4 groups. Age at the onset, BVAS scores, DEI scores, serum creatinine levels, and serum CRP levels are shown as median values.
| UK, n = 147 | Japan, n = 312 | p | EUVAS, n = 254 | JMAAV, n = 48 | |
|---|---|---|---|---|---|
| Period | 1999–2012 | 2002–2012 | 1995–2006 | 2008–2010 | |
| MPA:RLV | 130:17 | 277:35 | 235:19 | 48:0 | |
| Male:Female, (female rate) | 81:66 (44.9%) | 142:170 (54.5%) | 0.06 | 133:121 (47.6%) | 17:31 (64.6%) |
| Age at onset, yrs (range) | 64.8 (14.9–89.0) | 71.0 (16.0–94.0) | < 0.01 | 64.5 (17.2–86.1) | 70.0 (26.0–79.0) |
| MPO/p-ANCA-positive | 102 (69.4%) | 299 (95.8%) | < 0.01 | 173 (69.8%) | 48 (100%) |
| PR3/c-ANCA-positive | 33 (22.4%) | 10 (3.2%) | < 0.01 | 69 (27.8%) | 0 |
| ANCA double-positive | 3 (2.0%) | 8 (2.6%) | 1.00 | 4/248 (1.6%) | 0 |
| ANCA negative | 15 (10.2%) | 11 (3.5%) | < 0.01 | 10/248 (4.0%) | 0 |
| BVAS (range) | Not done | Not done | 15 (4–45) | 12.5 (0–34) | |
| DEI (range) | 5.0 (2–13) | 5.0 (2–13) | 0.37 | Not done | Not done |
| Creatinine, μmol/l (range) | 221.9 (58.3–1882.9) | 159.1 (26.5–2130.4) | < 0.01 | 335.0 (54.8–1670.8) | 108.7 (35.4–998.9) |
| CRP, mg/l (range) | 72.0 (1.0–350.0) | 62.7 (0.2–383.1) | 0.12 | 41.0 (0.3–552.0) | 65.3 (0.5–313.0) |
| Followup, mos (range) | 49.0 (0–152) | 34.0 (0–128) | 62.7 (0.2–135.6) | 15.6 (0–25.0) |
In the EUVAS database, 6 patients had a missing ANCA status. P value was calculated by the chi-square test for proportions comparing the UK and Japan. In those analyses where the expected frequency was < 5 in 1 or more cells, the p value was calculated using the Fisher’s exact test. P value was calculated using the Mann-Whitney U test for other distributions comparing the UK and Japan. EUVAS: European Vasculitis Society; JMAAV: Japanese patients from the MPO-ANCA-associated vasculitis trial; ANA: antineutrophil cytoplasmic antibody; MPA: microscopic polyangiitis; RLV: renal limited vasculitis; BVAS: Birmingham Vasculitis Activity Score; DEI: disease extent index; creatinine: serum creatinine levels; CRP: C-reactive protein; MPO: myeloperoxidase; PR3: proteinase 3.