Table 3 Clinical features by human leukocyte antigen B27 status
|  | Alla (n = 156) | HLA-B27 positive (n = 69) | HLA-B27 negative (n = 87) | p Value |
|---|---|---|---|---|
Demographics and clinical findings, n (%) or median (IQR) | ||||
 Age in years | 11.5 (9.6, 13.6) | 12.3 (10.3, 14.1) | 11.0 (8.8,13.2) | <0.01 |
 Sex, male | 100 (64.1) | 50 (72.5) | 50 (57.5) | 0.05 |
 Race, Caucasian | 129 (82.7) | 59 (85.5) | 70 (80.5) | 0.66 |
 Active joint count | 2 (1–4) | 3 (2–5) | 2 (1–4) | <0.01 |
 Tender entheses count | 2 (2–4) | 2 (1–3) | 2 (2–5) | 0.01 |
 MRI-defined sacroiliitis | 22 (57.9) | 15 (83.3) | 7 (35.0) | <0.01 |
 Polyarticular onset | 36 (23.1) | 20 (29.0) | 16 (18.4) | 0.15 |
 ANA-positive | 31 (21.4) | 10 (15.6) | 21 (25.9) | 0.13 |
 CRP, abnormal/elevated | 31 (28.4) | 13 (31.0) | 18 (26.9) | 0.65 |
 ESR, abnormal/elevated | 57 (41.9) | 34 (54.8) | 23 (31.1) | <0.01 |
Outcome measures, median (IQR) | ||||
 Physician disease activity (0–10) | 2.4 (2–3) | 2 (2–3) | 2.6 (2–4) | 0.07 |
 Juvenile Spondyloarthritis Disease Activity Index (JSpADA) (0–8) | 3 (2.5–4) | 3.5 (2.5–4) | 3 (2.5–3.5) | 0.04 |
 Patient/parent disease activity (0–10) | 4 (2–6) | 4 (2–5) | 4 (2–6) | 0.63 |
 Function (CHAQ) (0–3) | 0.625 (0–1) | 0.375 (0–1) | 0.625 (0–1) | 0.85 |
 Patient/parent pain (0–10) | 4 (2–7) | 4 (3–7) | 4 (2–7) | 0.71 |
 Juvenile Arthritis Disease Activity Score, excluding ESR (cJADAS) (0–30) | 9 (5–13) | 9 (5–13) | 9 (5–14) | 0.98 |
ILAR criteria, n (%) | ||||
 Acute, symptomatic uveitis | 7 (4.5) | 4 (5.8) | 3 (3.5) | 0.48 |
 Arthritis in a male over 6 years of age | 93 (59.6) | 50 (72.5) | 43 (49.4) | <0.01 |
 Family history of HLA-B27-associated disease | 18 (11.5) | 7 (10.1) | 11 (12.6) | 0.63 |
 Sacroiliac tenderness or lumbosacral pain | 46 (29.5) | 20 (29.0) | 26 (29.9) | 0.9 |