Description of patients at baseline
| Baseline evaluation | Definite AS (n = 847) | Probable AS (n = 176) | p Value |
|---|---|---|---|
| AS, ankylosing spondylitis; CRP, C reactive protein; BASDAI, Bath ankylosing spondylitis disease activity index; BASFI, Bath ankylosing spondylitis functional index; BASMI, Bath ankylosing spondylitis metrology index; NSAID, non-steroidal anti-inflammatory drugs. Symptom duration, disease duration since symptoms in years; disease duration, disease duration since diagnosis in years; disease duration <1 month, diagnosis was established within 1 month before the in-depth clinical profiling; MTX, methotrexate; SSZ, sulphasalazine. | |||
| Definite AS and probable AS are defined according to the New York modified criteria.16 | |||
| Percentages are given, except for continuous data: *mean (SD). | |||
| Male sex | 68% | 49% | <0.001 |
| HLA-B27 (n = 816) | 83% | 77% | 0.074 |
| Ever arthritis | 58% | 56% | 0.576 |
| Ever enthesitis | 50% | 52% | 0.573 |
| Elevated CRP | 37% | 18% | <0.001 |
| Syndesmophytes | 49% | 15% | <0.001 |
| Bamboo spine | 21% | 0% | <0.001 |
| Hip involvement | 27% | 15% | <0.001 |
| BASDAI* | 5.3 (2.1) | 4.7 (2.0) | <0.001 |
| BASDAI ⩾4 | 75% | 66% | 0.014 |
| BASFI* | 5.1 (2.5) | 3.6 (2.4) | <0.001 |
| BASMI* | 3.6 (2.4) | 2.4 (1.7) | <0.001 |
| Symptom duration* | 18.0 (12) | 9.3 (9) | <0.001 |
| Disease duration* | 12.0 (66) | 5.8 (40) | <0.001 |
| Disease duration <1 month | 6% | 12% | 0.003 |
| Age* | 45 (11) | 40 (12) | <0.001 |
| Psoriasis | 11% | 11% | 0.846 |
| Uveitis (ever) | 27% | 17% | 0.002 |
| Crohn’s disease | 8% | 7% | 0.854 |
| Ulcerative colitis | 3% | 2% | 0.678 |
| Ever MTX | 19% | 18% | 0.616 |
| Ever SSZ | 61% | 53% | 0.056 |
| Ever azathioprine | 4% | 7% | 0.102 |
| At least 2 NSAIDs used | 92% | 82% | 0.001 |
| Current NSAIDs | 72% | 63% | 0.020 |