| Criteria | All | Exposure to montelukast | |
| Yes | No | ||
| Subjects (n) | 78 | 20 | 58 |
| Mean (SD) age (years) | 53.9 (13.8) | 51.3 (13.0) | 54.8 (13.9) |
| Sex (M/F), n | 43/35 | 9/11 | 34/24 |
| Prior asthma, n (%) | 76/78 (97) | 20/20 (100) | 56/58 (97) |
| Disease presentation, n (%) | |||
| Polyposis | 48/77 (62) | 13/20 (65) | 35/57 (61) |
| Sinusitis | 67/78 (86) | 19/20 (95) | 48/58 (83) |
| Pulmonary infiltrate | 49/78 (63) | 12/20 (60) | 37/58 (64) |
| Eosinophilic alveolitis | 28/77 (36) | 7/20 (35) | 21/57 (37) |
| Alveolar haemorrhage | 3/78 (4) | 1/20 (5) | 2/58 (3) |
| Peripheral nerve involvement | 50/78 (64) | 13/20 (65) | 37/58 (64) |
| Cardiac involvement | 30/78 (38) | 6/20 (30) | 24/58 (41) |
| Cutaneous involvement | 26/78 (33) | 7/20 (35) | 19/58 (33) |
| Arthritis | 12/78 (15) | 3/20 (15) | 9/58 (16) |
| Glomerulonephritis | 8/78 (10) | 3/20 (15) | 5/58 (9) |
| ANCA positivity, n (%) | 30/74 (41) | 6/19 (32) | 24/55 (44) |
| C-ANCA or anti-PR3* | 6/74 (8) | 0 | 6/55 (11) |
| Anti-MPO* | 20/74 (27) | 5/19 (26) | 15/55 (27) |
| Histological proof, n (%) | 45/78 (58) | 11/20 (55) | 34/58 (59) |
| Peripheral eosinophilia†, n (%) | 72/78 (92) | 18/20 (90) | 54/58 (93) |
| Classification criteria satisfied, n (%) | |||
| ACR | 75/78 (96) | 19/20 (95) | 56/58 (97) |
| Lanham | 44/78 (56) | 12/20 (60) | 32/58 (55) |
| Both | 41/78 (53) | 11/20 (55) | 30/58 (52) |
ACR, American College of Rheumatology; ANCA, antineutrophil cytoplasm antibodies; C-ANCA, diffuse cytoplasm labelling pattern; MPO, myeloperoxidase; PR3, proteinase 3; SD, standard deviation.
*One patient with C-ANCA and anti-MPO specificity.
†Defined as either absolute count >1500/mm3 or relative count >10% of white blood cells.