| Diagnosis | Etanercept monotreatment (n = 100) | Etanercept and methotrexate (n = 504) |
| Female (%) | 58 (58%) | 345 (67%) |
| Age at disease onset, mean (SD) (median) | 7.5 (4.6) (7.0) | 7.6 (4.6) (7.4) |
| Disease duration (years), mean (SD) (median) | 5.5 (4.6) (3.9) | 4.9 (3.6 (3.9) |
| Age at start of treatment, mean (SD) (median) | 13.1 (4.5) (14.9) | 12.5 (4.39) (12.9) |
| ANA (positive/negative/unknown) | 40%/47%/13% | 42%/56%/2% |
| HLA-B27 (positive/negative/unknown) | 31%/54%/15% | 23%/68%/9% |
| Systemic arthritis (systemic onset JIA), n (%) | 8 (8%) | 57 (11.3%) |
| Seronegative polyarticular JIA. n (%) | 24 (24%) | 158 (31.3%) |
| Seropositive polyarticular JIA, n (%) | 3 (3%)* | 65 (12.9%)* |
| Persistent oligoarticular JIA, n (%) | 8 (8%) | 23 (4.6%) |
| Extended oligoarticular JIA, n (%) | 17 (17%) | 73 (14.5%) |
| Enthesitis related arthritis, n (%) | 27 (27%)† | 66 (13.1%)† |
| Psoriasis and arthritis, n (%) | 7 (7%) | 41 (8.1%) |
| Unclassified JIA, n (%) | 6 (6%) | 21 (4.2%) |
*p<0.01, χ2 test; †p<0.001, χ2 test.
ANA, antinuclear antibody; HLA, human leukocyte antigen.