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SAT0253 Patients With Non-As Axial SPA Have Similar Prevalence Compared to as, But Worse Perceived Health. Results from a Population Based Study.
  1. U. Lindström1,
  2. A. Bremander2,
  3. S. Bergman2,
  4. E. Haglund2,
  5. I. F. Petersson3,
  6. L. T. Jacobsson1
  1. 1Rheumatology and Inflammation Research, Sahlgrenska Academy, Gothenburg
  2. 2Section of Rheumatology
  3. 3Orthopedics, Clinical Sciences, Lund University, Sweden

Abstract

Background Non-radiographic axial spondyloarthritis (SpA) is emerging as a treatable disease comparable to ankylosing spondylitis (AS), but less well studied. Previous studies have described a reversed gender distribution, with AS being more prevalent in the male population and non-radiographic axial SpA more prevalent in the female population. Recent studies have also indicated a similar benefit from treatment with TNF-inhibitors.

Objectives The aim of this study was to estimate the prevalence of non-radiographic axial SpA and compare the patient reported outcome measures (PROMS) to that of AS, in Southern Sweden.

Methods All health care seeking individuals, ≥18 years, given a SpA-diagnosis, according to the ICD-10 (M45.9, M072, M460, M461, M468, M469, M074, M705 and L405 or M071 or M073), either in primary or specialized care, (N = 5771), during 2003 - 2007, were identified through the regional health care register in Skåne, a county in Southern Sweden with 1.2 million inhabitants (SpAScania cohort). In 2009 they were all sent a questionnaire (response rate; 48%), including questions concerning inflammatory back pain (IBP), the SpA-associated comorbidities constituting the ASAS-criteria (IBD, Ps, Uveitis/tendinitis, heredity), PROMS (BAS-indices, VAS-pain/fatigue/global, EQ5D) and previous/current medication.

Non-AS axial SpA was defined as having an ICD10 code supporting a diagnosis of SpA without having one of AS (M45.9), in combination with > 3 months of back pain the last year and the presence of ≥2 of the SpA associated comorbidities. Record review support the notion of using AS as a substitute for radiographic changes. For the “non imaging arm” of the ASAS criteria for axial disease, we used the ICD10 codes above as a substitute for HLA-B27 status. Assuming similar answers from the questionnaire non-responders, prevalence rates were estimated for non-AS axial SpA and AS.

Results Among responders 742 had an AS-diagnosis and 640 fulfilled the study criteria for non-AS axial SpA. The frequency of men was 60.5% in the AS group and 29.5% in the non-AS axial SpA group. The prevalence of AS was 0.13% (95% CI; 0.115-0.148) and for non-AS axial SpA 0.11 % (95% CI; 0.096-0.130), with a reverse gender distribution. The means of the PROMs and frequency of comorbidities were higher in the non-AS axial SpA vs both the AS, and the subgroup of AS individuals reporting back pain (BP) > 3months during the last year. Self-reported present use of TNF-inhibitors were similar between the groups (Image 1).

Conclusions Prevalence rates for AS and non-AS axial SpA were similar, with a reverse gender distribution. The results suggest that at a population level the proportion with non-AS axial SpA is at least as large as that of AS and report lower levels of perceived health status and similar frequencies of SpA-related comorbidities (except psoriasis) and treatment with TNF-inhibitors, supporting the validity for the used definition in future research.

Disclosure of Interest None Declared

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