Baseline characteristics of patients and controls
| Baseline characteristics | JIA (n=400) | HC (n=2176) |
|---|---|---|
| Age at sampling in years, mean (±SD)* | 9.4 (±4.5) | 7.9 (±5.5) |
| Measles vaccinations* | ||
| 0 Measles vaccination | 14 (4%) | 130 (6%) |
| 1 Measles vaccination | 192 (48%) | 1377 (63%) |
| 2 Measles vaccinations | 194 (48%) | 669 (31%) |
| Mumps vaccinations* | ||
| 0 Mumps vaccination | 16 (4%) | 360 (16%) |
| 1 Mumps vaccination | 205 (51%) | 1588 (73%) |
| 2 Mumps vaccinations | 179 (45%) | 228 (11%) |
| Rubella vaccinations* | ||
| 0 Rubella vaccination | 16 (4%) | 135 (6%) |
| 1 Rubella vaccination | 205 (51%) | 1814 (83%) |
| 2 Rubella vaccinations | 179 (45%) | 227 (11%) |
| Diphtheria and tetanus vaccination* | ||
| 1–4 Diphtheria and tetanus vaccinations | 79 (20%) | 735 (34%) |
| 5–6 Diphtheria and tetanus vaccinations | 321 (80%) | 1441 (66%) |
| Female | 259 (65%) | |
| JIA subtype | ||
| Oligoarticular JIA, persistent | 159 (40%) | |
| Oligoarticular JIA, extended | 38 (10%) | |
| Polyarticular JIA, RF positive | 13 (3%) | |
| Polyarticular JIA, RF negative | 110 (27%) | |
| Systemic onset JIA | 64 (16%) | |
| Enthesitis-related JIA | 10 (3%) | |
| Psoriatic arthritis | 6 (1%) | |
| Disease characteristics | ||
| Age at onset in years, mean (±SD) | 5.9 (±4.0) | |
| Duration of JIA at sampling in years, median (IQR) | 1.7 (5.4) | |
| Disease activity and medication use | ||
| Joints with active arthritis, median (IQR) | 2 (4) | |
| Joints with limitation of motion, median (IQR) | 1 (2) | |
| PGA of disease activity, median (IQR) | 2.0 (2.6) | |
| ESR in mm/h, median (IQR) | 11 (30) | |
| Uveitis | 25 (6%) | |
| Patients with active disease at time of sampling | 205 (51%) | |
| Patients on methotrexate | 93 (23%) | |
| Methotrexate dose (mg/m2 per week), median (IQR) | 10.0 (8.7) | |
| Patients on NSAID | 246 (62%) | |
| Patients on other DMARD† | 24 (6%) | |
| Patients on anti-TNFα therapy | 8 (2%) | |
| Patients on oral glucocorticosteroids | 28 (7%) | |
| Glucocorticosteroids dose (mg/day), median (IQR) | 10.0 (10.0) | |
Unless otherwise indicated, frequency (percentage) is depicted.
↵* p Value <0.001.
↵† Sixteen patients used sulphasalazine and eight used ciclosporin at the time of sampling.
DMARD, disease-modifying antirheumatic drugs; ESR, erythrocyte sedimentation rate; HC, healthy controls; JIA, juvenile idiopathic arthritis; NSAID, non-steroidal anti-inflammatory drugs; PGA, physician global assessment of disease activity; RF, rheumatoid factor; TNFα, tumour necrosis factor alpha.