Ankylosing Spondylitis / Axial Spondyloarthritis
Ankylosing Spondylitis / Axial Spondyloarthritis is indexed under Musculoskeletal & Connective Tissue, Spondyloarthritis. Also known as AS, axSpA, radiographic axSpA.
- US prevalence
- ~0.5-1% of adults (~1.7-2.7 million for axSpA spectrum) Source: SAA; ACR. This figure comes from a professional society, registry, or study rather than a federal source. Label: REPORTED.
- ICD-10-CM codes
- M45, M45.9
- Typical onset
- Typically 20-40 years; mean onset ~26
- Course
- progressive
- Body systems
- musculoskeletal, ophthalmologic
- Sex differences
- Historically M:F ~3:1; axSpA spectrum closer to equal
- Racial and ethnic differences
- Associated with HLA-B27; prevalence varies by ancestry
What this page does not establish
These figures describe populations, not individuals, and none of them is a diagnosis or a treatment recommendation. Prevalence estimates are approximate and reflect published ranges. Disparity figures are reported patterns, not causes.
Taxonomy last reviewed 2026-05-19. Each figure on the interactive page carries its own source and retrieval date, which can be later than this review.
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