POS0240 GEOGRAPHICAL PREVALENCE OF A FAMILY HISTORY IN PATIENTS WITH AXIAL SPONDYLOARTHRITIS AND ITS ASSOCIATION WITH HLA-B27: DATA FROM THE WORLDWIDE ASAS-PERSPA STUDY
Authors: M. Van Lunteren, A. Boel, C. López-Medina, J. Sieper, D. Van der Heijde, F. A. Van Gaalen
Journal: Annals of the Rheumatic Diseases (2021)

Background: Research has shown that in axial spondyloarthritis (axSpA) patients, the most common form of spondyloarthritis (SpA) in a family history is axSpA. Moreover, the association between a positive family history of spondyloarthritis (PFH) and HLA-B27 carriership is driven by a PFH of axSpA and possibly acute anterior uveitis (AAU), but not by other forms of SpA. However, this research was limited to mostly Western European patients. Objectives: To investigate the impact of geographical region on family history and its association between HLA-B27 carriership in patients with axSpA around the world. Methods: Data from the Assessment in SpondyloArthritis international Society (ASAS) peripheral involvement in Spondyloarthritis (ASAS-perSpA) study was used. Analyses were restricted to patients with an axSpA diagnosis who had information available on HLA-B27 status and family history. The frequencies of any PFH, as well as a PFH for axSpA, psoriasis, AAU, inflammatory bowel disease (IBD) and reactive arthritis (ReA), were determined per geographical region. Logistic regression models were built to assess the effect of HLA-B27 status on the occurrence of any PFH and each disease in a PFH in the total population and also stratified per geographical region. Results: In total, 2,048 patients were included from 4 regions: Asia (n=545), Europe &amp; North America (n=840), Latin America (n=202), and Middle East &amp; North Africa (n=461). Patients had a median age (IQR) of 40 (31-50) years, 31% were female, and had a disease duration of 11 (5-20) years. A PFH of axSpA was the most common in all geographical regions, regardless of HLA-B27 carriership. A PFH of psoriasis and IBD appeared to be more common in HLA-B27 negative patients, and a PFH of ReA was rare in all patients (figure 1). Univariable logistic regression models showed an association between a PFH and HLA-B27 carriership in the Asian population, but this association does not seem apparent in the other geographical regions (table 1). Contrary, a PFH of axSpA was associated with HLA-B27 carriership in all geographical regions except the Middle East &amp; North Africa (table 1). An association between HLA-B27 carriership and a PFH of psoriasis was solely present in Middle East &amp; North Africa (OR=0.4, 95% CI 0.2-0.7), and an association with a PFH of IBD was solely present in Europe &amp; North America (OR=0.5, 95% CI 0.3-0.9). No associations were found for HLA-B27 carriership and a PFH of AAU and ReA in any geographical region. There was also no effect modification of geographical region (p=0.43) on the association between HLA-B27 status and a PFH. Table 1. Univariable associations between HLA-B27 carriership and a positive family history of axSpA patients in the perSpA cohort stratified per geographical region HLA-B27+ n=1,609 HLA-B27 - n=439 OR (95% CI ) p-value Any positive family history Total population Yes 631 149 1.26 (1.01-1.57 ) 0.044 No 978 290 Ref. Per geographical region Asia 157/487 11/58 4.23 (2.26-7.91 ) &lt;0.001 Europe &amp; North America 270/658 67/182 1.19 (0.89-1.61) 0.241 Latin America 50/164 9/38 1.65 (0.80-3.39) 0.175 Middle East &amp; North Africa 154/300 62/161 0.74 (0.53-1.02) 0.063 Positive family history for axSpA Total population Yes 518 90 1.84 (1.43-2.38 ) &lt;0.001 No 1,087 348 Ref. Per geographical region Asia 144/487 11/58 4.19 (2.24-7.83 ) &lt;0.001 Europe &amp; North America 196/658 30/182 2.09 (1.40-3.13 ) &lt;0.001 Latin America 37/164 3/38 3.95 (1.21-12.89 ) 0.023 Middle East &amp; North Africa 141/300 46/161 0.98 (0.69-1.40) 0.917 axSpA, axial spondyloarthritis; CI, confidence interval; HLA-B27, human leucocyte antigen B27; OR, odds ratio Conclusion: Throughout the world, axSpA was the most common form of SpA in a family history. In all regions except Middle East &amp; North Africa, a PFH of axSpA was associated with HLA-B27 carriership in axSpA patients. These results suggest that the current expert definition of a PFH of SpA should be revaluated. Acknowledgements: We would like to thank all ASAS-perSpA investigators and members of the scientific committee. Disclosure of Interests: None declared