Patient selection: chronic back pain (>= 3 months) with age at onset < 45 years
Criteria for the diagnosis of axial spondyloarthritis - one or both of the following:
(1) sacroiliitis on imaging studies AND >= 1 spondyloarthritis features
(2) presence of HLA-B27 AND >= 2 other spondyloarthritis features
Sacroiliitis on imaging studies - one or both of the following:
(1) active inflammation identified on MRI highly suggestive of sacroiliitis
(2) definite radiographic sacroiliitis using the modified New York criteria
Spondyloarthritis features:
(1) inflammatory back pain
(2) arthritis
(3) enthesitis involving the heel
(4) uveitis
(5) dactylitis
(6) psoriasis
(7) idiopathic inflammatory bowel disease (ulcerative colitis or Crohn's disease)
(8) good response to NSAIDs
(9) family history of spondyloarthritis
(10) HLA-B27
(11) elevated CRP (associated with chronic back pain)
Performance:
• The authors considered a series of different data sets.
• This data set had the best performance with a sensitivity of 83% and specificity of 84%. The imaging arm had a sensitivity of 66% and specificity of 97%.
