Table 2

 Comparison between human leucocyte antigen B27 (HLA-B27)-positive and HLA-B27-negative patients and between patients with and without inflammation on magnetic resonance imaging of the sacroiliac joints in the early spondyloarthritis clinic cohort

HLA-B27Inflammation on MRIHLA-B27 or inflammation
Present(n = 31)Absent(n = 37)Present(n = 22)Absent(n = 46)Present(n = 37)Absent(n = 31)
BASDAI, Bath Ankylosing Spondylitis Disease Activity Index; BASFI, Bath Ankylosing Spondylitis Functional Index; HLA-B27, human leucocyte antigen B27; IBD, inflammatory bowel disease; IBP, inflammatory bowel pain; MRI, magnetic resonance imaging; NA, not applicable; NSAID, non-steroidal anti-inflammatory drug; SpA, spondyloarthritis.
Extra-spinal SpA features: asymmetric arthritis, Achilles tendinitis, dactylitis, inflammatory bowel disease, acute anterior uveitis and psoriasis.
Data are percentages unless otherwise indicated.
Inflammation on MRI5216NANA590
HLA-B27 positiveXX7333840
History or presence of IBD723520526
History or presence of acute anterior uveitis191114151910
History or presence of psoriasis133218261632
Family history of ankylosing spondylitis482732395455
Raised acute-phase reactants453846445131
Improvement on NSAIDs (%)814191448429
Mean BASDAI (SD)3.6 (1.8)3.7 (4.4)3.8 (2.1)3.6 (2.2)3.7 (1.9)3.6 (3.3)
Mean BASFI (SD)2.5 (1.8)2.7 (2.3)2.7 (2.0)2.6 (2.2)2.6 (1.8)2.6 (2.2)
Checklist IBP
    <5 criteria present305736483561
    5 criteria present704364526539
Presence of extra-spinal SpA features
    0 SpA features392436283019
    1 or 2 SpA features556755656274
    ⩾3 SpA features689786