Table 2.

Patient characteristics at time of enthesitis-related arthritis classification

	All subjects (n = 234)
Demographics, median (IQR) or n (%)
Age in years	11.6 (9.8–13.7)
Sex, male	169 (72.2)
Race, Caucasian	194 (82.9)
Family history of HLA-B27-associated disease	36 (15.4)
Clinical characteristics, median (IQR) or n (%)
HLA-B27 positivity	135 (59.2)
Active joint count	2 (1–4)
Tender entheses count	2 (1–4)
MRI-defined sacroiliitis (n = 45 with imaging)	25 (55.6)
Polyarticular onset	52 (22.2)
ANA-positive	49 (23.4)
CRP, abnormal/elevated	39 (26.9)
ESR, abnormal/elevated	93 (45.8)
Patient-/physician-reported outcomes, median (IQR)
Physician global disease activity assessment (0–10)	2.5 (2–4)
Juvenile Spondyloarthritis Disease Activity Index (JSpADA) (0–8)	3 (2.5–4)
Juvenile Arthritis Disease Activity Score (cJADAS), excluding ESR (0–30)	9 (5–14)
Patient/parent global disease activity assessment (0–10)	4 (2–6)
Function (CHAQ) (0–3)	0.563 (0–1)
Patient/parent pain assessment (0–10)	4 (2–7)

Abbreviations: IQR Interquartile range, HLA Human leukocyte antigen, MRI Magnetic resonance imaging, ANA Antinuclear antibody, CRP C-reactive protein, ESR Erythrocyte sedimentation rate, CHAQ Childhood Health Assessment Questionnaire

Denominators for clinical characteristics varied because of missing data: HLA-B27 status (n = 228), magnetic resonance imaging-defined sacroiliitis (n = 45), ANA (n = 209), CRP (n = 145), ESR (n = 203), physician global disease activity assessment (n = 126), JSpADA (n = 116), patient/parent global disease activity assessment (n = 102), CHAQ (n = 120), patient/parent pain assessment (n = 129), cJADAS (JADAS3–10) (n = 86)