Table 3

 Description of patients with AS as a function of the presence of anti-TNF treatment at inquiry

Baseline evaluationDefinite ASProbable AS
Without anti-TNFat query(n = 340)With anti-TNF at query (lag time <1 month) (n = 121)With anti-TNFat query (all patients) (n = 263)p ValueWithout anti-TNF at query (n = 116)With anti-TNF at query (n = 22)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; 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.
Elevated CRP26%56%48%<0.00116%18%0.840
Bamboo spine16%25%24%0.0230%0%NA
Hip involvement22%37%36%<0.00114%32%0.038
BASDAI*4.7 (2.2)6.4 (1.6)6.1 (1.7)<0.0014.4 (2.0)6.0 (1.6)0.001
BASFI*4.4 (2.6)6.1 (2.0)5.9 (2.3)<0.0013.2 (2.2)5.6 (2.0)0.000
BASMI*3.0 (2.3)4.1 (2.2)4.0 (2.4)<0.0012.3 (1.6)2.9 (1.8)0.179
Age*45 (11)44 (11)44 (11)0.09440 (12)38 (12)0.607
Symptom duration18 (12)19 (13)19 (13)0.16310 (8)11 (9)0.286
Any extra-articular manifestation39%42%44%0.34223%55%0.003
BASDAI ⩾463%95%90%<0.00160%91%0.006
BASDAI ⩾4 and failing NSAID55%90%85%<0.00151%84%0.008
BASDAI ⩾4 and failing NSAID + elevated CRP at the time of evaluation17%55%45%<0.00122%8%0.085