AB0496 COMPARISON OF THE DISTRIBUTION BY DEPARTMENT OF THE PREVALENCE OF SPONDYLOARTHRITIS AND INFLAMMATORY BOWEL DISEASES IN METROPOLITAN FRANCE AND THEIR EVOLUTION BETWEEN 2008 AND 2018
Authors: O. Fakih, C. Prati, D. Wendling, F. Verhoeven
Journal: Annals of the Rheumatic Diseases (2021)

Background: Epidemiology of spondyloarthritis (SpA) has been rarely described in France. One study based on a phone survey found a prevalence of 0.30% in 2001 [1], and another study based on a national cohort showed an estimated prevalence of 0.43% in 2010 [2]. To our knowledge, there is no data regarding the geographical distribution of SpA in France. Furthermore, it is known that SpA occurs in up to 13% of patients with inflammatory bowel disease (IBD), and that there is a significant north-south gradient in IBD cases in France. Objectives: To determine the prevalence of SpA and IBD in metropolitan France and compare the geographical distribution of SpA and IBD in 2008 and 2018. Methods: Age-and sex-standardized prevalences were collected from data freely available on the French national health insurance website concerning patients with long-term disability (LTD) #27 (SpA) and #24 (IBD). Data for December 31, 2008 and December 31, 2018 were collected. National data are available by diagnosis coded according to the ICD-10 classification, and data by department only concern all patients benefiting from a given LTD. Results: National prevalence of SpA is estimated at 0.11% in 2008 (43.8% of women, average age 50 years) and 0.27% in 2018 (54% of women, average age 53 years). National prevalence of IBD is estimated at 0.19% in 2008 (55.6% of women, average age 46 years) and 0.27% in 2018 (55% of women, average age 49 years). Standardized prevalences by pathology are detailed in Table 1. Standardized prevalences by department are shown in Figure 1. Table 1. Standardized SpA and IBD prevalence (per 100000) by disease in 2008 and 2018. Ankylosing Spondylitis Psoriatic Arthritis Crohn’s Disease Ulcerative colitis 2008 95 31 103 84 2018 181 57 153 126 Figure 1. Standardized SpA and IBD prevalence by department in 2008 and 2018. SpA prevalences found in this study are lower than those indicated in the literature: 0.27% versus 0.43% [2]. This may be explained by the fact that not all patients suffering from SpA or IBD benefit from LTD. Moreover, there is a 2.42-fold increase over ten years, which may correspond to the increase in prescription of biotherapies, which requires the benefit of LTD. North-south gradient in the prevalence of IBDs has been found, which is not the case for SpA, which seems to be less prevalent in the north-eastern quarter of the country. These differences in geographical distribution appear to be stable between 2008 and 2018. While IBD and SpA share many physiopathological similarities, their different geographical distributions suggest the importance of different environmental factors in the development of each condition. Conclusion: The north-south gradient in the distribution of IBD in metropolitan France is not found in SpA. Despite an increasing prevalence, these distributions appear to be stable over time suggesting an important impact of environmental factor in the expression of these close diseases. References: [1]Saraux A, Guillemin F, Guggenbuhl P, et al. Prevalence of spondyloarthropathies in France: 2001. Ann Rheum Dis 2005; 64 :1431–5. doi:10.1136/ard.2004.029207 [2]Costantino F, Talpin A, Said-Nahal R, et al. Prevalence of spondyloarthritis in reference to HLA-B27 in the French population: results of the GAZEL cohort. Ann Rheum Dis 2015; 74 :689–93. doi:10.1136/annrheumdis-2013-204436 Disclosure of Interests: None declared.