Table 3

Baseline observed patient and disease characteristics per latent class in SPACE and DESIR

SPACEDESIR
‘Axial’
(n=64)
‘IBP+peripheral’
(n=92)
‘At risk’
(n=99)
‘No SpA’
(n=210)
‘Axial’
(n=110)
‘IBP+peripheral’
(n=137)
‘At risk’
(n=329)
Clinical and demographic
 Age at baseline (years)30323031313334
 Male gender 66 383225 73 4340
 Symptom duration (years)1222212
Imaging
 Inflammation on MRI-SIJ (ASAS) 86 302 88 228
 BME on MRI-Spine (≥5 lesions) 28 201 20 01
 Radiographic sacroiliitis (mNY) 34 1112 59 52
 ≥1 syndesmophyte on X-Spine37031166
SpA features
 Elevated CRP (≥6 mg/dL) 50 222420 56 3916
 Good response to NSAIDs (ever) 59 89 3218 97 84 82
 Peripheral arthritis (ever)17 47 397 83 0
 Dactylitis (ever)2 19 023 55 0
 Heel enthesitis (ever)9 72 12324 59 47
 Current arthritis/enthesitis/dactylitis48 87 64 68 56 88 65
 HLA-B27 86 36 85 0 93 52 52
 Family history of SpA38 52 72 24474342
 Psoriasis (ever)9 35 177 29 16
 Uveitis (ever)137 15 28 12 8
 IBD (ever)3 15 09155
 Inflammatory back pain 67 100 69 50100*100*100*
 Number of SpA features (0–9)†3 5 213 4 2
ASAS classification criteria
 ASAS axSpA criteria 98 45604 93 5854
 ASAS pSpA criteria48 70 561556 82 44
 ASAS SpA criteria‡ 98 787917 99 8964
  • Values are means for continuous variables or percentages for binary variables.

  • *By study design all patients in DESIR have IBP.

  • †Peripheral arthritis, heel enthesitis, dactylitis, psoriasis, uveitis, inflammatory bowel disease, good response to NSAIDs, elevated CRP and family history of SpA.

  • ‡Fulfilment of either ASAS axSpA or ASAS pSpA classification criteria. Values in bold highlight discriminant features across latent classes. Values in italic highlight dominant features (probability >50%) within each class. SpA features are positive if ‘ever present’ (any time in the past and/or baseline).

  • ASAS, Assessment of SpondyloArthritis international Society; axSpA, axial spondyloarthritis; BME, bone marrow oedema; CRP, C reactive protein; DESIR, DEvenir des Spondylarthopathies Indifférenciées Récentes; IBD, inflammatory bowel disease; mNY, modified New York criteria; NSAIDs, non-steroidal anti-inflammatory drug; pSpA, peripheral spondyloarthritis; SIJ, sacroiliac joints; SPACE, SPondyloArthritis Caught Early; X-Spine, radiograph of the spine.