Patient characteristics at study enrolment by HLA-B27 status
| HLA-B27 positive, n=78 | HLA-B27 negative, n=40 | p Value | All patients, n=118 | |
|---|---|---|---|---|
| Age at study start, mean (SD) | 13.9 (2.5) | 12.6 (2.8) | 0.008 | 13.5 (2.7) |
| Male, n (%) | 60 (77) | 26 (65) | 0.168 | 86 (73) |
| Symptom duration (years), mean (SD) | 2.3 (2.1) | 2.1 (1.5) | 0.551 | 2.2 (1.9) |
| Duration since diagnosis (years), mean (SD) | 1.6 (1.8) | 1.4 (1.5) | 0.788 | 1.5 (1.7) |
| Positive family history for SpA, n (%) | 29 (37) | 31 (78) | 0.0001 | 60 (51) |
| CRP (mg/L), mean (SD) | 9.8 (15.9) | 7.7 (13.1) | 0.001 | 9 (14.9) |
| CRP ≥5 mg/L, n (%) | 40 (51) | 8 (20) | 0.0001 | 48 (50.5) |
| ESR (mm/hour), mean (SD) | 19 (18.3) | 10.9 (9.9) | 0.002 | 16.2 (16.4) |
| ESR >20 mm/hour, n (%) | 20 (25) | 7 (18) | 0.319 | 27 (23) |
CRP, C reactive protein; ESR, erythrocyte sedimentation rate; SpA, spondyloarthritis.