Role of HLA-B27 in the comorbidities observed in Axial Spondyloarthritis: data from COMOSPA.

To analyze the potential association between the presence of HLA-B27 and the different comorbidities observed in Axial Spondyloarthritis patients.A comparative cross-sectional study including Axial Spondyloarthritis patients from COMOSPA registry. COMOSPA is a worldwide registry that includes a wide set of anthropometric and clinical variables from 3984 patients with Spondyloarthritis. The registry also includes the most frequent comorbidities observed in Spondyloarthitis such as obesity, hypertension, diabetes, hyperlipidemia, heart ischemic disease, stroke, renal failure, neoplasms, peptic ulcer, diverticulitis, chronic obstructive pulmonary disease, and the presence of osteoporosis. A descriptive analysis and a multiple logistic regression model was performed including all variables assessed.2370 patients fulfilled ASAS criteria of Axial Spondyloarthritis patients and were included in the study. 1858 (78.4%) of them were HLA-B27 positive. HLA-B27 positive Axial Spondyloarthritis patients presented significantly higher percentage of male sex, longer disease duration, higher percentage of definite Ankylosing Spondylitis, higher CRP levels, and were also more frequent tobacco consumers and excessive alcohol intakers compared to the negatives. However, disease activity measured by BASDAI, BASFI and ASDAS-CRP were all significantly higher in the HLA-B27 negative patients compared to the positive ones. The only association observed between any comorbidity and presence of gen HLA-B27 was the presence of osteoporosis, even after adjusting in the multivariate analysis for all variables assessed.The association observed between the gen HLA-B27 and the presence of osteoporosis in Axial Spondyloarthritis patients could be of great relevance given the impact of osteoporosis in the phenotypical frame of these patients.