Ann Rheum Dis 66:633-638 doi:10.1136/ard.2006.060293
  • Extended report

Are there gender differences in severity of ankylosing spondylitis? Results from the PSOAS cohort

  1. Wonuk Lee1,
  2. John D Reveille2,
  3. John C Davis Jr3,
  4. Thomas J Learch4,
  5. Michael M Ward5,
  6. Michael H Weisman1
  1. 1Division of Rheumatology, Cedars-Sinai Medical Center, Los Angeles, California, USA
  2. 2Division of Rheumatology and Clinical Immunogenetics, University of Texas Health Science Center at Houston, Houston, Texas, USA
  3. 3Division of Rheumatology, University of California, San Francisco, California, USA
  4. 4Department of Radiology, Keck School of Medicine of the University of Southern California, Los Angeles, California, USA
  5. 5National Institute of Arthritis and Musculoskeletal and Skin Diseases, National Institutes of Health, Bethesda, Maryland, USA
  1. Correspondence to:
    Professor M H Weisman
    Cedars-Sinai Medical Center, Division of Rheumatology, 8700 Beverly Boulevard, B-131 Los Angeles, CA 90048, USA; weisman{at}
  • Accepted 2 November 2006
  • Published Online First 24 November 2006


Objective: To examine the clinical and radiographic features in men and women in the Prospective Study of Outcomes in Ankylosing Spondylitis cohort, a large well-defined cross-sectional study of patients with AS, in order to understand the influence of gender in determining the severity of ankylosing spondylitis.

Methods: Extensive clinical assessments and spine radiographs were performed in 302 men and 100 women with AS of ⩾20 years duration. Radiographs were scored using the Bath Ankylosing Spondylitis Radiographic Index Spine (BASRI-spine) score (range 2–12). Functional impairment was measured by the Bath Ankylosing Spondylitis Functional Index (BASFI) and the Health Assessment Questionnaire for the Spondyloarthropathies (HAQ-S).

Results: Radiographic severity was worse among men. The unadjusted median BASRI-spine score for men was 10, compared with 6.5 for women (p<0.001). Functional disability, as measured by the BASFI and HAQ-S, was not different between men and women. However, after adjusting for radiographic spinal damage, women were found to report worse functioning than men at any given level of radiographic damage. Women had a slightly earlier age of disease onset; however, disease duration was identical in both groups. Women more frequently reported family histories of AS in first-degree relatives and were more likely to be treated with intra-articular steroids, sulphasalazine and prednisone.

Conclusions: Among patients with longstanding AS, men have more severe radiographic changes; findings of treatment differences suggest that women may have more peripheral arthritis. At any given level of radiographic damage, self-reported functional limitations were worse for women.


  • Published Online First 24 November 2006

  • Competing interests: None declared.