Table 2

Selection of possible combinations of features in patients with low back pain presenting to primary care. The pretest probability refers to the prevalence of axial spondyloarthritis (SpA) among patients with chronic back pain, the post-test probabilities result from the presence (+) or absence (−) of various SpA features

Pretest prob. (%)Possible combination of clinical, laboratory, or imaging SpA featuresPost-test prob. (%)
5IBP (+) plusFamily history (+)51
5IBP (+) plusHeel pain (+)35
5IBP (+) plusUveitis (+)54
5IBP (+) plusSynovitis (+)39
5IBP (+) plusDactylitis (+)42
5IBP (+) plusFamily history (+) plusHeel pain (+)78
5IBP (+) plusUveitis (+) plusNSAID (+)85
5IBP (+) plusHeel pain (+) plusSynovitis (+) plusAlternating buttock pain (+)89
5IBP (+) plusFamily history (+) plusHeel pain (+) plusNSAID (+)95
5IBP (+) plusHeel pain (+) plusHLA-B27 (+)83
5IBP (+) plusNSAIDs (+) plusHLA-B27 (+)88
5IBP (+) plusHeel pain (+) plusHLA-B27 (-)6
5IBP (+) plusNSAID (+) plusHLA-B27 (-)8
5IBP (+) plusDactylitis (+)ESR/CRP (+)62
5IBP (+) plusHLA-B27 (+) plusESR/CRP (+)78
5IBP (+) plusHLA-B27 (+) plusESR/CRP (-)47
5IBP (+) plusHLA-B27 (+) plusMRI (+)93
5IBP (+) plusHLA-B27 (+) plusMRI (-)14
5IBP (+) plusHeel pain (+) plusHLA-B27 (+) plusMRI (-)35