Baseline characteristics of 30 patients with very early inflammatory back pain
| Mean (SD) age (years) | 31.1 (5.4) |
| Men, n (%) | 15 (50) |
| Median (IQR), (range) BMI (kg/m2) | 23.3 (4.2), (19.2–35.9) |
| Median (IQR), (range) disease duration (weeks) | 24 (38), (2–260) |
| HLA-B27 positive, n (%) | 17 (56.7) |
| Median (IQR), (range) back pain during day on VAS | 55.0 (34.0), (0–95) |
| Median (IQR), (range) back pain during night on VAS | 60 (44), (0–100) |
| Mean (SD) BASDAI | 6.22 (2.07) |
| Mean (SD) BASFI | 4.81 (2.64) |
| Median (IQR), (range) CRP (mg/l) | 10 (17), (5–65) |
| Patients on NSAIDs, n (%) | 24 (80) |
| Presence of BMO on SIJ | |
| MRI | |
| Median (IQR), (range) MRI BMO SIJs (range for MRI scoring method 0–24) | 3.0 (8), (0–19) |
| Presence of BMO on MRI SIJs, n (%) | 29 (96.7) |
| Presence of BMO on MRI lumbar spine, n (%) | 5 (16.7) |
| BMD (g/cm2) | |
| Mean (SD) femoral necks | 1.03 (0.13) |
| Mean (SD) total hips | 1.06 (0.13) |
| Mean (SD) spine L2–4 | 1.24 (0.15) |
| Mean (SD) hands | 0.45 (0.05) |
| T-score | |
| Mean (SD femoral necks | 0.06 (1.08) |
| Mean (SD) total hips | 0.13 (1.05) |
| Mean (SD) spine L2–4 | 0.18 (1.29) |
BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Disease Functional Index; BMD, bone mineral density; BMI, body mass index; BMO, bone marrow oedema; CRP, C-reactive protein; HLA-B27, human leucocyte antigen B27; NSAIDs, non-steroidal anti-inflammatory drugs; SIJs, sacroiliac joints; VAS, visual analogue scale (0–100 mm).