Table 3 ERA patients’ clinical characteristics by the presence of SIJ structural change

Male, n (%)

26 (86.7%)

9 (81.8%)

0.651

Age of onset in years, median (IQR)

12 (10–15)

10 (9–11)

0.064

Buttock pain at presentation, n (%)

3 (11.1%)

2 (20%)

0.597

Low back pain at presentation, n (%)

9 (33.3%)

0 (0%)

0.079

Hip involvement within 1^st 6 months, n (%)

10 (35.7%)

4 (40%)

1

Ankle involvement within 1^st 6 months, n (%)

1 (3.6%)

2 (20%)

0.164

Duration from onset to diagnosis in months, median (IQR)

9 (4–17.5)

2 (1–5)

*0.009

Duration from diagnosis to 1^st MRI of SIJ in months, median (IQR)

2.5 (0–42.8)

15 (2–128.5)

0.447

Duration of disease, median (IQR)

12.4 (7.4–19.3)

6.9 (4.3–19.6)

0.204

Abnormal mSchober at diagnosis, n (%)

7 (35%)

0 (0%)

0.137

CRP at presentation (mg/L), median (IQR)

14.6 (1.75–35.5)

7.9 (2.9–22.6)

0.645

ESR at presentation (mm/hr), mean (SD)

39.5 (29.6)

46.1 (17.5)

0.534

Latest BASDAI, median (IQR)

1.2 (0.2–2.2)

1.16 (0.31–2.25)

0.864

Latest BASFI, median (IQR)

0.23 (0.05–0.89)

0.35 (0.07–0.85)

0.845

mSchober at last visit (cm), median (IQR)

6 (5–6)

7 (5–7)

0.227

Biologic use, n (%)

11 (36.7%)

2 (18.2%)

0.451