Table 1.
Baseline demographic characteristics, clinical and imaging variables in the FORCAST study population with radiographic progression data for the spine over at least 2 years
| All patients (N=431) | Available MRI (N=232) | No available MRI (N=199) | p Value | |
|---|---|---|---|---|
| Age (mean (SD)) | 42.4 (12.5) | 40.8 (11.9) | 44.2 (12.9) | 0.01 |
| Males (N (%)) | 318 (73.8%) | 169 (72.8%) | 149 (74.9%) | 0.67 |
| Symptom duration (mean (SD) years) | 18.3 (11.5) | 17.1 (10.8) | 19.8 (12.3) | 0.04 |
| Smokers* | ||||
| Current, N (%) | 74 (21.1%) | 37 (19.6%) | 37 (23%) | 0.51 |
| Pack years smoked (mean (SD)) | 6.5 (9.4) | 5.4 (8.7) | 7.8 (10.1) | 0.01 |
| N (%) smoked >10 pack years | 85 (25.7%) | 39 (22.0%) | 46 (29.9%) | 0.13 |
| BASDAI (mean (SD)) | 5.1 (2.4) | 5.1 (2.4) | 5.2 (2.5) | 0.47 |
| ASDAS (mean (SD)) | 3.8 (1.4) | 3.8 (1.4) | 3.8 (1.5) | 0.95 |
| CRP (mean (SD) mg/L) | 14.5 (20.1) | 12.4 (16.4) | 17 (23.5) | 0.16 |
| N (%) HLA-B27 positive† | 325 (84%) | 175 (84.1%) | 150 (83.8%) | 1.0 |
| N (%) on NSAIDs | 347 (80.5%) | 188 (81%) | 159 (79.9%) | 0.81 |
| N (%) on TNF-α inhibitor | 266 (61.7%) | 134 (57.8%) | 132 (66.3%) | 0.07 |
| mSASSS (mean (SD)) | 17.1 (20.6) | 13.7 (18.1) | 21.2 (22.6) | 0.0002 |
| Duration of follow-up (mean (SD)) (range) months |
31.9 (13.6) (18–105) |
30.9 (12.6) (18–105) |
33.1 (14.6) (18–98) |
0.22 |
| ΔmSASSS (mean (SD)) | 2.3 (3.8) | 2.4 (4.3) | 2.2 (3.2) | 0.69 |
| ΔmSASSS progression rate (mean (SD)) mSASSS units/year | 0.83 (1.3) | 0.85 (1.3) | 0.81 (1.2) | 0.65 |
| N (%) with no progression over ≥2 years | 204 (47.3%) | 105 (45.3%) | 99 (49.7%) | 0.38 |
| N (%) with average ΔmSASSS progression rate >0 units/year | 227 (52.7%) | 127 (54.7%) | 100 (50.3%) | 0.38 |
| N (%) with average ΔmSASSS progression rate ≥1 unit/year for ≥2 years | 136 (31.6%) | 76 (32.8%) | 60 (30.2%) | 0.67 |
| N (%) with new syndesmophyte‡ | 49 (23.7%) | 30 (23.3%) | 19 (24.4%) | 0.87 |
*Data from 350 patients (331 with pack years data).
†Data from 387 patients.
‡Patients with 2-year follow-up (±2-month window; n=207).
ASDAS, Ankylosing Spondylitis Disease Activity Score; BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; CRP, C-reactive protein; FORCAST, Follow Up Research Cohort in Ankylosing Spondylitis; HLA, human-leucocyte-antigen; mSASSS, modified Stoke Ankylosing Spondylitis Spine Score; NSAID, non-steroidal anti-inflammatory drug; TNF, tumour necrosis factor.