Table 3 Description of patients with AS as a function of the presence of anti‐TNF treatment at inquiry.
| Baseline evaluation | Definite AS | Probable AS | |||||
|---|---|---|---|---|---|---|---|
| Without anti‐TNF at query (n = 340) | With anti‐TNF at query (lag time <1 month) (n = 121) | With anti‐TNF at query (all patients) (n = 263) | p Value | Without anti‐TNF at query (n = 116) | With anti‐TNF at query (n = 22) | p Value | |
| MALE | 60% | 73% | 73% | 0.001 | 46% | 64% | 0.123 |
| HLA‐B27 | 77% | 92% | 88% | 0.001 | 76% | 68% | 0.451 |
| Arthritis | 22% | 27% | 29% | 0.029 | 28% | 46% | 0.114 |
| Enthesitis | 17% | 17% | 21% | 0.206 | 24% | 27% | 0.754 |
| Elevated CRP | 26% | 56% | 48% | <0.001 | 16% | 18% | 0.840 |
| Syndesmophytes | 38% | 57% | 45% | <0.001 | 16% | 15% | 0.920 |
| Bamboo spine | 16% | 25% | 24% | 0.023 | 0% | 0% | NA |
| Hip involvement | 22% | 37% | 36% | <0.001 | 14% | 32% | 0.038 |
| BASDAI* | 4.7 (2.2) | 6.4 (1.6) | 6.1 (1.7) | <0.001 | 4.4 (2.0) | 6.0 (1.6) | 0.001 |
| BASFI* | 4.4 (2.6) | 6.1 (2.0) | 5.9 (2.3) | <0.001 | 3.2 (2.2) | 5.6 (2.0) | 0.000 |
| BASMI* | 3.0 (2.3) | 4.1 (2.2) | 4.0 (2.4) | <0.001 | 2.3 (1.6) | 2.9 (1.8) | 0.179 |
| Age* | 45 (11) | 44 (11) | 44 (11) | 0.094 | 40 (12) | 38 (12) | 0.607 |
| Symptom duration | 18 (12) | 19 (13) | 19 (13) | 0.163 | 10 (8) | 11 (9) | 0.286 |
| Psoriasis | 10% | 12% | 12% | 0.560 | 9% | 23% | 0.051 |
| Uveitis | 25% | 26% | 31% | 0.096 | 12% | 32% | 0.018 |
| IBD | 9% | 9% | 10% | 0.901 | 5% | 14% | 0.116 |
| Any extra‐articular manifestation | 39% | 42% | 44% | 0.342 | 23% | 55% | 0.003 |
| BASDAI ⩾4 | 63% | 95% | 90% | <0.001 | 60% | 91% | 0.006 |
| BASDAI ⩾4 and failing NSAID | 55% | 90% | 85% | <0.001 | 51% | 84% | 0.008 |
| BASDAI ⩾4 and failing NSAID + elevated CRP at the time of evaluation | 17% | 55% | 45% | <0.001 | 22% | 8% | 0.085 |
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; IBD, inflammatory bowel disease: ulcerative colitis or Crohn's disease; anti‐TNF, anti‐tumour necrosis factor alfa therapy
Definite AS and probable AS are defined according to the New York modified criteria.16
Percentages are given, except for continuous data: * mean (SD).
p Values are calculated for the contrast without anti‐TNF at inquiry vs with anti‐TNF at inquiry for all patients.