Diagnosing: Recognizing and proactively identifying patients with nr-axSpA

nr-axSpA criteria in patients with back pain for ≥3 months and age of onset <45 years53,54*

Imaging criteria

Sacroiliitis on imaging and ≥1 SpA feature
Active inflammation on MRI highly suggestive
of sacroiliitis associated with SpA

Clinical criteria

HLA-B27+ and ≥2 other SpA features

ASAS classification criteria were developed to identify patients with axSpA (nr-axSpA and AS).53*

Probability of diagnosis53,55,56

The clinical diagnosis of axSpA (nr-axSpA and AS) relies upon a combination of SpA features and imaging.55
The percentages below indicate the percentage of patients who are eventually diagnosed with nr-axSpA.

Among patients with chronic back pain in GP/PCP office:

  • The first step to evaluating a patient with chronic back pain for axSpA is to determine whether the back pain is inflammatory or mechanical in nature57

Presence of IBP:

  • IBP is characterized by age at onset <40, insidious onset, improvement with exercise, no improvement with rest, and pain at night with improvement upon getting up53,55

Presence of one or two additional SpA features:

  • Evaluate the patient for the presence of SpA features, including enthesitis, dactylitis, uveitis, a positive family history of SpA, CD, alternating buttock pain, psoriasis, asymmetrical arthritis, a positive response to NSAIDs, and an elevated ESR or CRP to evaluate inflammation53
  • Positive HLA-B27 test result is associated with an increased likelihood that the patient has axSpA53
  • At least three axSpA features will increase the probability to 80% to 95%55
  • HLA-B27(+) (80%-90%55†)
  • Imaging: X-ray SIJ (+) = AS57
  • X-ray SIJ (–), MRI SIJ (+) = nr-axSpA57

Prevalence of extraspinal manifestations in nr-axSpA patients

Enthesitis up to 44%58

Peripheral arthritis up to 41%58

Psoriasis up to 11%37

Subclinical IBD up to 42%59

Uveitis up to 12%53

Dactylitis up to 7%53

*Derived from full ASAS axSpA classification criteria, which differentiates criteria for nr-axSpA and AS. Probability varies based on number of SpA features present.
Prevalence includes all axial and peripheral SpA disease states.
AS: ankylosing spondylitis; ASAS: Assessment of SpondyloArthritis international Society; CD: Crohn’s disease; CRP: C-reactive protein; ESR: erythrocyte sedimentation rate; GP: general practitioner; HLA-B27+: human leukocyte antigen-B27 positive; IBD: inflammatory bowel disease; IBP: inflammatory back pain; MRI: magnetic resonance imaging; nr-axSpA: non-radiographic axial spondyloarthritis; NSAID: nonsteroidal anti-inflammatory drug; PCP: primary care physician; SIJ: sacroiliac joint; SpA: spondyloarthritis.