Differences in the prevalence of ankylosing spondylitis in primary and secondary care: only one-third of patients are managed in rheumatology

Linda E. Dean, Gary J. Macfarlane, Gareth T. Jones* (Corresponding Author)

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)
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Objective. Knowing not only the prevalence of SpA, but also the proportion managed in rheumatology, has implications for health care planning. The aims of this study were to determine the prevalence of SpA and the proportion managed in rheumatology and to examine differences in group characteristics. Methods. For the primary care population, we used the Primary Care Clinical Informatics Unit Research (PCCIUR) electronic primary care database, covering one-third of the Scottish population. Patients with AS, and various extraspinal manifestations were identified using Read Codes. For secondary care, we used the Scotland Registry for Ankylosing Spondylitis, which collected data on clinically diagnosed AS patients >15 years of age seen in rheumatology clinics between 2010 and 2013. Prevalence estimate denominators were computed using the adult PCCIUR and Scottish 2011 mid-year population estimates, respectively. Differences in the characteristics of both patient groups were examined using simple descriptive statistics. Results. The prevalence of AS in primary care was 13.4/10 000 (95% CI 12.8, 14.0) and 4.7/10 000 in rheumatology (95% CI 4.5, 4.9). Rheumatology patients were younger overall and at diagnosis (mean age 51 vs 62 years and 35 vs 38, respectively; both P < 0.001) and more likely to have a history of uveitis (34 vs 22%), IBD (12 vs 6%) and psoriasis (14 vs 6%) (all P < 0.001). Conclusions. This is the first study to estimate the prevalence of clinically diagnosed AS in primary and secondary care simultaneously, indicating that only one-third of patients are managed in rheumatology. This has important ramifications for health care planning and indicates a large ‘silent’ proportion of patients who may have serious pathology and would benefit from additional assessment in a specialist clinic.
Original languageEnglish
Pages (from-to)1820-1825
Number of pages6
Issue number10
Early online date27 Jun 2016
Publication statusPublished - Oct 2016

Bibliographical note

We would like to thank all the clinicians and research nurses who facilitated recruitment and data collection. In particular we would like to thank the SIRAS steering committee, especially Prof Roger Sturrock (chair) and Dr David Marshall (vice chair). We would also like to thank the SIRAS coordinating centre study team, in particular Elizabeth Jones, Giles O’Donovan, Nabi Moaven-Hashemi and Flora Joyce.

We would like to thank the PCCIUR research group for providing data, in particular Dr Chris Burton, Dr Margaret Watson, Dr Karen Lefevre, Katie Wilde and Nathan Staudt.

All authors jointly conceived of the idea of the study. G.T.J. managed the day-to-day running of the study and data collection. G.J.M. was chief investigator of the SIRAS study and was involved in overseeing the analysis. L.E.D. conducted the analysis, under the supervision of G.T.J., and produced the first draft of the article. G.J.M. and G.T.J. provided critical comments and revisions to the final manuscript.

SIRAS was funded by unrestricted grants from Pfizer and AbbVie. L.E.D. conducted the analysis for this study while being partly funded by a Medical Research Council Doctoral Training Grant.

Funding: No specific funding was received from any bodies in the public, commercial or not-for-profit sectors to carry out the work described in this article.


  • ankylosing spondylitis
  • spondyloarthritis
  • prevalence
  • epidemiology


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