Table 1. Clinical characteristics of study cohort.
| All patients (n = 365) | Severe AS (n = 195) | Mild AS (n = 170) | p | |
| Age at onset, year | 37.0±8.6 | 41.6±8.1 | 33.0±6.8 | <0.001 |
| Male | 340 (93.2) | 174 (89.2) | 166 (97.6) | 0.001 |
| Disease duration, year | 14.1±6.8 | 16.7±7.3 | 11.9±5.4 | <0.001 |
| Smoker (n = 322) | 201 (62.4) | 114 (74.0) | 87 (51.8) | <0.001 |
| HLA-B27 (n = 344) | 334 (97.1) | 151 (98.7) | 183 (95.8) | 0.195 |
| ESR, mm/hr (n = 197) | 20.5±23.9 | 23.2±26.4 | 18.1±21.4 | 0.135 |
| CRP, mg/dL (n = 194) | 1.2±2.2 | 1.4±2.7 | 1.1±1.6 | 0.381 |
| mSASSS, range 0–72 | ||||
| Cervical spine | 12.2±11.0 | 19.4±12.5 | 6.0±2.7 | <0.001 |
| Lumbar spine | 10.8±13.1 | 21.9±11.5 | 1.2±2.1 | <0.001 |
| Total | 23.1±21.9 | 41.5±19.7 | 7.2±3.6 | <0.001 |
| *Continuous NSAID intake (n = 161) | 44 (27.3) | 24 (33.3) | 20 (22.5) | 0.124 |
Data were shown to mean ± SD or n (%).
*Continuous NSAID intake was defined as 70 or more the score. AS; ankylosing spondylitis, HLA-B27: human leukocyte antigen-B27; ESR: erythrocyte sedimentation rate; CRP: C-reactive protein; Msasss: modified stokes AS spine score; NSAID: non-steroidal anti-inflammatory drugs.