| Baseline characteristics | Number | Radiographic progression at year 2* | |
|---|---|---|---|
| N (%) | Adjusted odds-ratio [95% CI] | ||
| Smoking yes | 108 | 9 (8.3%) | 3.3 |
| Smoking no | 216 | 7 (3.2%) | [1.0–11.5] |
| HLA B27 positive | 187 | 15 (8.0%) | 12.6 |
| HLA B27 negative | 139 | 1 (0.7%) | [2.3–273.5] |
| MRI positive | 81 | 14 (17.3%) | 48.8 |
| MRI negative | 226 | 1 (0.4%) | [9.3–903.9] |
↵* Radiographic progression = switch from a baseline non radiographic to a 2 years radiographic status according to the mNY criteria.