Table 1

Characteristics of the Nordic juvenile idiopathic arthritis cohort at the baseline visit and the 18-year follow-up

DemographicsnBaselinen18-year follow-up*
Gender female n (%)427290 (67.9)427290 (67.9)
Age at onset of symptoms (years), median IQR4275.7 (2.7–9.7)
Time to study visit (years), median IQR4270.6 (0.5–0.7)42717.6 (16.8–18.4)
Full-time employed or student, n (%)424306 (72.2)
Transferred directly to adult rheum. care, n (%)†427163 (38.2)
Transferred later to adult rheum. care, n (%)†42760 (14.1)
ILAR category, n (%)
 Oligoarthritis persistent427232 (54.3)427115 (26.9)
 Oligoarthritis extended42785 (19.9)
 RF-negative polyarthritis42790 (21.1)42775 (17.6)
 RF-positive polyarthritis4277 (1.6)4276 (1.4)
 Enthesitis-related arthritis42731 (7.3)42741 (9.6)
 Psoriatic arthritis4278 (1.9)42728 (6.6)
 Undifferentiated42745 (10.5)42763 (14.7)
 Systemic42714 (3.3)42714 (3.3)
 ANA positive‡382140 (36.6)
 HLA-B27 positive41089 (21.7)
Treatment at the visit, n (%)
 NSAID417224 (53.7)26777 (28.8)
 sDMARD42778 (18.3)42784 (19.7)
 bDMARD4227 (1.7)42783 (19.4)
Disease activity measures
 Number of active joints, median IQR4271 (0–3)4270 (0–0)
 PhGA, median IQR2291.0 (0.5–2.9)4160 (0–1.0)
 PaGA, median IQR2511.0 (0.1–2.9)3960.5 (0–2.5)
 ESR (mm/h), median IQR34414 (8–28)2775 (2-9)
 cJADAS10 score, median IQR2224.4 (1.7–8.5)3891.0 (0–4.0)
 CHAQ/HAQ score, median IQR2601.0 (0–3.0)3960 (0–0.4)
 Pain VAS, median IQR2470.3 (0–1.1)3960.5 (0–3.0)
 Morning stiffness ≥15 min, n (%)418223 (53.3)37967 (17.7)
 Uveitis, n (%)42419 (4.5)42795 (22.3)
Damage, n (%)
 JADI-A>0258042769 (16.2)
 JADI-E>0258042743 (10.1)
  • *104 participated through a standardised telephone interview at the 18-year visit. For the 323 patients attending the visit, PaGA was available for 308 and PhGA for 321 participants.

  • †After the regular follow-up at the paediatric rheumatologist was finished due to age limit, the patient was transferred directly or not to adult care.

  • ‡ANA measured by immunofluorescence on Hep-2 cells, performed at least twice with a minimum of 3 months apart.

  • A, articular damage (0-72); ANA, antinuclear antibodies; bDMARD, biologic disease-modifying antirheumatic drug; CHAQ/HAQ, Child Health Assessment Questionnaire/Health assessment questionnaire (0–3); cJADAS10, clinical Juvenile Arthritis Disease Activity score (0–30); E, extra-articular damage (0–17); ESR, erythrocyte sedimentation rate; HLA-B27, human leucocyte antigen B27; ILAR, International League of Associations for rheumatology; JADI, Juvenile Arthritis Damage Index; NSAID, non-steroidal anti-inflammatory drug; PaGA, patient or parental global assessment of disease impact on well-being; PhGA, physician’s global assessment of disease activity; RF, rheumatoid factor; sDMARD, synthetic disease-modifying antirheumatic drug; VAS, Visual Analogue Scale (0–10).