Table 2

Sensitivity, specificity, percentage of axSpA diagnosis missed and erroneous diagnoses of axSpA by the algorithm in the SPACE-cohort and ASAS-cohort according to the three external standards ASAS axial SpA criteria, LR-product probability ≥80% and diagnosis rheumatologist

Sensitivity (%)Specificity (%)Correct classified (%)False-negatives (%)False-positives (%)
SPACE
ASAS axial SpA
Original72.686.380.910.88.3
Modification 181.781.481.57.011.5
Modification 289.883.786.03.810.2
LR-product probability ≥80%
Original85.594.791.15.73.2
Modification 192.493.493.03.23.8
Modification 210092.695.50.04.5
Diagnosis rheumatologist
Original66.283.776.414.09.6
Modification 172.378.375.811.512.7
Modification 278.580.479.68.911.5
ASAS
ASAS axial SpA
Original72.684.177.515.66.9
Modification 186.778.383.17.69.3
Modification 289.483.088.86.17.6
LR-product probability ≥80%
Original83.599.390.29.50.3
Modification 196.085.691.22.26.6
Modification 297.290.796.61.64.2
Diagnosis rheumatologist
Original65.379.270.721.38.0
Modification 177.972.275.913.610.8
Modification 279.675.680.012.79.8
  • Modification 1: IBP 3/5 instead of 4/5.

  • Modification 2: IBP as additional SpA-feature instead of entry criterion.

  • ASAS, Assessment of SpondyloArthritis international Society; axSpA, axial Spondyloarthritis; LR-product, Likelihood Ratio-product, SPACE, SPondyloArthritis Caught Early.