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THU0376 Prevalence of Peripheral and Extra-Articular Disease in Ankylosing Spondylitis versus Non-Radiographic Axial Spondyloarthritis: A Meta-Analysis
  1. J.J. De Winter1,
  2. L.J. van Mens1,
  3. D. van der Heijde2,
  4. R. Landewé1,
  5. D.L. Baeten1,3
  1. 1Department of Clinical Immunology and Rheumatology, Amsterdam Rheumatology and immunology Center, Academic Medical Center/University of Amsterdam, Amsterdam
  2. 2Department of Rheumatology, Leiden University Medical Center, Leiden
  3. 3Department of Experimental Immunology, Academic Medical Center/University of Amsterdam, Amsterdam, Netherlands


Background Axial spondyloarthritis (axSpA) is a common chronic inflammatory disease with predominantly axial symptoms. Besides axial symptoms, the disease is characterized by peripheral (arthritis, enthesitis, dactylitis), and extra-articular (uveitis, psoriasis, inflammatory bowel disease (IBD)) disease manifestations. A much debated question is whether the radiographic form (defined as ankylosing spondylitis or AS) and the non-radiographic form (nr-axSpA) of axSpA represent subsets of the same disorder or if they are distinct disease entities (1–4). Hypothesizing that AS and nr-axSpA reflect subsets of a single disease entity and have similar disease burden, we performed a meta-analysis of published studies of axial SpA in order to assess if the prevalence of peripheral and extra-articular disease manifestations is similar in AS and nr-axSpA.

Objectives The objective of this meta-analysis was to assess the prevalence of peripheral and extra-articular disease manifestations in AS and nr-axSpA.

Methods We performed a systematic literature search to identify publications describing the prevalence of peripheral and extra-articular disease manifestations in patients with AS and nr-axSpA. We assessed the risk of bias, between-study heterogeneity and extracted data. Pooled prevalence and prevalence differences were calculated.

Results Eight studies including 2236 AS patients and 1242 nr-axSpA patients were included. Seven out of 8 studies were longitudinal cohort studies. There was a male dominance in AS (70.4%; 95% CI 64.4–76.0%) but not in nr-axSpA (46.8%; 95% CI 41.7–51.9), which was independent from HLA-B27 prevalence. HLA-B27 prevalence was similar in AS (78.0%; 95% CI 73.9–81.9%) and nr-axSpA (77.4%; 95% CI 68.9–84.9%). The pooled prevalence of arthritis (29.7% (95% CI 22.4–37.4%) versus 27.9% (95% CI 16.0–41.6%)), enthesitis (30.4% (95% CI 3.7–65.8%) versus 34.1% (95% CI 4.7–71.0%)), dactylitis (6.0% (95% CI 4.7–7.5%) versus 6.0% (95% CI 1.9–12.0%)), psoriasis (10.2% (95% CI 7.5–13.2%) versus 10.9% (95% CI 9.1–13.0%)) and IBD (4.1% (95% CI 2.3–6.5%) versus 6.4% (95% CI 3.6–9.7%)) were similar in AS and nr-axSpA. The pooled uveitis prevalence was higher in AS (23.0% (95% CI 19.2–27.1%)) than in nr-axSpA (15.9% (95% CI 11.8–20.4%)).

Conclusions Peripheral and extra-articular manifestations are equally prevalent in AS and nr-axSpA, except for uveitis, which is slightly more prevalent in AS. These data support the concept that AS and nr-axSpA belong to one pathogenic entity with similar disease manifestations.

  1. Wallis D, et al. Ankylosing spondylitis and nonradiographic axial spondyloarthritis: part of a common spectrum or distinct diseases? J Rheumatol 2013;40:2038–41.

  2. Rudwaleit M, Khan MA, Sieper J. Commentary: The challenge of diagnosis and classification in early ankylosing spondylitis: Do we need new criteria? Arthritis Rheum 2005;52:1000–1008.

  3. Robinson PC, et al. Axial spondyloarthritis: a new disease entity, not necessarily early ankylosing spondylitis. Ann Rheum Dis 2013;72:162–4.

  4. Kiltz U, et al. Do patients with non-radiographic axial spondylarthritis differ from patients with ankylosing spondylitis? Arthritis Care Res 2012;64:1415–22.

Disclosure of Interest None declared

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