Patient characteristics at last follow-up
| Parameters | Missings | |
| n | 1306 | |
| Age, years, mean (SD) | 23.1 (4.1) | 0 |
| Female, N (%) | 886 (67.8) | 0 |
| JIA category, N (%) | 0 | |
| Systemic JIA | 66 (5.1) | |
| Persistent oligoarthritis | 117 (9.0) | |
| Extended oligoarthritis | 227 (17.4) | |
| RF-negative polyarthritis | 350 (26.8) | |
| RF-positive polyarthritis | 115 (8.8) | |
| Enthesitis-related arthritis | 268 (20.5) | |
| Psoriatic arthritis | 116 (8.9) | |
| Undifferentiated arthritis | 47 (3.6) | |
| ANA positive (at BiKeR enrollment), N (%) | 536 (41.0) | 18 (1.4) |
| HLA-B27 positive, N (%) | 326 (25.0) | 18 (1.4) |
| Disease duration, years, mean (SD) | 13.6 (6) | 8 (0.6) |
| Physician′s global assessment of disease activity (NRS 0–10), mean (SD), n=621 | 1.8 (2.0) | 685 (52.5) |
| Patients in clinically inactive disease*, n (%), n=621 | 252 (40.6) | 685 (52.5) |
| Patient-reported disease activity (NRS 0–10), mean (SD) | 2.8 (2.3) | 1 (0.1) |
| Patient-reported pain (NRS 0–10), mean (SD) | 2.6 (2.4) | 2 (0.2) |
| Patient-reported fatigue (NRS 0–10), mean (SD) | 3.2 (2.8) | 1 (0.1) |
| HAQ total score (range 0–3), mean (SD) | 0.29 (0.52) | 14 (1.1) |
| Patient-reported HRQoL, SF-36, mental component summary score, mean (SD) | 49.3 (9.6) | 44 (3.4) |
| Patient-reported HRQoL, SF-36, physical component summary score, mean (SD) | 46.8 (10.8) | 44 (3.4) |
*Defined according to Wallace et al.45
ANA, antinuclear antibodies; bDMARD, biological disease modifying antirheumatic drug; HAQ, Health Assessment Questionnaire; HRQoL, health-related quality of life; JIA, juvenile idiopathic arthritis; NRS, Numerical Rating Scale; RF, rheumatoid factor; SF-36, Short Form-36; ys, years.