Table 2

Diagnosis and classification of patients (n=500) with ≤ one, two, three and ≥ four spondyloarthritis (SpA) features after medical history taking, physical examination and measurement of acute phase reactants, followed by sacroiliac imaging and HLA-B27 testing

Number of SpA featuresX-SI statusHLA-B27/MRI statusRheumatologist SpA diagnosis
yes
Rheumatologist SpA diagnosis
no
ASAS axSpA classification
yes
ASAS axSpA classification
no
0–1
n=159
X-SI+
n=9
HLA-B27+/MRI+44
HLA-B27+/MRI−112
HLA-B27−/MRI+11
HLA-B27−/MRI−22
X-SI−
n=150
HLA-B27+/MRI+617
HLA-B27+/MRI−71623
HLA-B27−/MRI+156147
HLA-B27−/MRI−29799
Mean level of confidence regarding diagnosis (SD)6.9 (2.3)7.5 (2.4)
2
n=143
X-SI+
n=16
HLA-B27+/MRI+1414
HLA-B27+/MRI−11
HLA-B27−/MRI+11
HLA-B27−/MRI−
X-SI−
n=127
HLA-B27+/MRI+1515
HLA-B27+/MRI−152035
HLA-B27−/MRI+527
HLA-B27−/MRI−115970
Mean level of confidence regarding diagnosis (SD)7.6 (1.9)6.7 (2.3)
3
n=79
X-SI+
n=5
HLA-B27+/MRI+33
HLA-B27+/MRI−11
HLA-B27−/MRI+11
HLA-B27−/MRI−
X-SI−
n=74
HLA-B27+/MRI+1717
HLA-B27+/MRI−11920
HLA-B27−/MRI+88
HLA-B27−/MRI−82129
Mean level of confidence regarding diagnosis (SD)8.0 (1.9)7.1 (2.0)
≥4
n=119
X-SI+
n=28
HLA-B27+/MRI+1515
HLA-B27+/MRI−
HLA-B27−/MRI+88
HLA-B27−/MRI−55
X-SI−
n=91
HLA-B27+/MRI+1616
HLA-B27+/MRI−21425
HLA-B27−/MRI+88
HLA-B27−/MRI−281442
Mean level of confidence regarding diagnosis (SD)8.0 (2.0)7.3 (1.7)
  • Diagnosis based on information after full diagnostic workup: medical history, physical examination, imaging and laboratory testing. ASAS axSpA criteria, ASAS criteria for axial spondyloarthritis. Mean level of confidence regarding diagnosis: 0 (not confident at all) through 10 (very confident).

  • AxSpA, axial spondyloarthritis; ASAS, Assessment of SpondyloArthritis international Society; HLA-B27, human leucocyte antigen B27; X-SI, radiograph of sacroiliac joints; SpA, spondyloarthritis.