Table 2

 Description of patients at baseline

Baseline evaluationDefinite 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 sex68%49%<0.001
HLA-B27 (n = 816)83%77%0.074
Ever arthritis58%56%0.576
Ever enthesitis50%52%0.573
Elevated CRP37%18%<0.001
Bamboo spine21%0%<0.001
Hip involvement27%15%<0.001
BASDAI*5.3 (2.1)4.7 (2.0)<0.001
BASDAI ⩾475%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 month6%12%0.003
Age*45 (11)40 (12)<0.001
Uveitis (ever)27%17%0.002
Crohn’s disease8%7%0.854
Ulcerative colitis3%2%0.678
Ever MTX19%18%0.616
Ever SSZ61%53%0.056
Ever azathioprine4%7%0.102
At least 2 NSAIDs used92%82%0.001
Current NSAIDs72%63%0.020