Worldwide Differences in Clinical Phenotype of Axial Spondyloarthritis

Purpose of Review: This review aims to describe the variations in the clinical presentation of axial spondyloarthritis (axSpA) across the globe. Recent Findings: We searched the PubMed database and screened more than 1360 articles; 60 of them were selected based on relevance to the topic being discussed and the goals of the review. Most of the clinical manifestations, including IBP, peripheral arthritis, and extra-articular involvement are seen in different regions of the world, but with appreciable clinical heterogeneity, possibly related to a smaller number of patients from some countries, and global variation in the prevalence of HLA-B27. For example, HLA-B27-positive patients have an earlier age of onset, higher prevalence of acute anterior uveitis, and greater familial occurrence. Peripheral arthritis and enthesitis are most commonly seen among axSpA patients from Latin America and Asia, whereas IBD appears to be slightly more common among Middle Eastern and North African patients. The main weakness encountered while reviewing these data is that some studies were small, and others were cross-sectional and retrospective; hence the inferences may have a selection bias. Summary: AxSpA is a very heterogenous disease with varied presentation across the globe, in part related to HLA-B27 positivity. It is imperative to further investigate the key regional differences as they impact timely disease recognition and initiation of early treatment. Therefore, there is a need for a large worldwide systematic study to capture the clinical picture of AxSpA in a more uniform manner.