Prevalence of Spondyloarthritis in Alaska Native and American Indian Peoples of Alaska

OBJECTIVE: The objective of this study was to determine the prevalence and clinical characteristics of spondyloarthritis (SpA) in Alaska Native and American Indian (AN/AI) peoples of Alaska. METHODS: We queried electronic health records from participating tribal health organizations within the Alaska Tribal Health System from 2012 to 2019 to identify adults with a potential diagnosis of SpA based on International Classification of Diseases, 9th or 10th revision codes. Medical records were abstracted to confirm the diagnosis and clinical characteristics. Adults who were alive at the end of the study period and had a confirmed clinician diagnosis of SpA were included in prevalence calculations. We determined whether included adults had medical record documentation of meeting SpA classification criteria. RESULTS: The age-adjusted prevalence of any form of SpA was 355 per 100,000 adults (95% CI 317-397); for psoriatic arthritis it was 162 (95% CI 137-191), and for ankylosing spondylitis it was 107 (95% CI 86-131). Two-thirds (67%) of adults with any form of SpA who were tested were HLA-B27 positive. Two-thirds of adults with SpA other than psoriatic arthritis (69.1%) had documentation in their medical record to confirm that they met clinical classification criteria for axial SpA. CONCLUSION: The prevalence of SpA in AN/AI peoples of Alaska is lower than previously reported in this population but is higher than in most populations previously studied. Understanding the increased prevalence of SpA in this population may help clinicians identify and treat the condition in AN/AI peoples.