Baseline characteristics of patients with radiographic axial spondyloarthritis
| Assessment | N=50*† |
| Male | 43 (86.0) |
| Age, years | 49.1 (9.9) |
| HLA-B27 positive | 42 (84.0) |
| BMI, kg/m2 | 26.8 (3.9) |
| Current smoking | 19 (38.8) |
| ASDAS | 2.6 (1.2) |
| ASDAS inactive disease (ASDAS<1.3) | 6 (12.8) |
| ASDAS low disease activity (1.3≤ ASDAS <2.1) | 11 (23.4) |
| ASDAS high disease activity (2.1≤ ASDAS ≤3.5) | 22 (46.8) |
| ASDAS very high disease activity (ASDAS >3.5) | 8 (17.0) |
| TNFi treatment | 12 (24.0) |
| NSAIDs treatment | 32 (64.0) |
| Patients with syndesmophytes‡ | 50 (100.0) |
| Patients with spine MRI-BME§ | 47 (94.0) |
| Cervical spine HU¶ | 319 (104.6) |
| Thoracic spine HU¶ | 195 (68.8) |
| Lumbar spine HU¶ | 153 (58.2) |
*Mean (SD) or no. (%).
†Missing values <10%: smoking status (n=1 patients); ASDAS variables (n=3 patients).
‡Defined as a patient with ≥1 quadrant per vertebra that received a CT Syndesmophytes Score ≥1 (absolute agreement of two readers).
§Defined as a patient with ≥1 quadrant per vertebra with MRI-BME (agreement of 2 out of 3 readers).
¶Average of the two readers’ scores.
ASDAS, Ankylosing Spondylitis Disease Activity Score; BME, bone marrow oedema; BMI, body mass index; HLA, human leucocyte antigen; HU, Hounsfield units; NSAIDs, non-steroidal anti-inflammatory drugs; TNFi, Tumour necrosis factor inhibitors.