Ankylosing spondylitis (AS), a form of inflammatory arthritis that impacts the lower spine and pelvic joints, is an inflammatory condition that can occur in people of any race or sex, but white men are most apt to carry a genetic mutation, HLA-B27, that increases the likelihood of developing this disease. When Black men or women do get AS, however, research shows they tend to have higher levels of disease activity.
That’s the main finding of a study, published in the Journal of Rheumatology, that examined data on AS patients from 26 health care systems gathered between 1999 and 2017. The authors noted that the low incidence of this disease among Black Americans has prevented scientists from adequately studying its impact on this group.
The total number of patients with AS studied in the database was 10,990; 8 percent were Black. Half of both races were male and half were female.
In this study, the researchers looked at inflammatory markers (erythrocyte sedimentation rate [ESR] and C-reactive protein [CRP]) and found that these markers were more apt to be elevated in Black ankylosing spondylitis patients compared to white AS patients.
They also learned that Black people with AS were more likely to have comorbid (co-existing) conditions, including anterior uveitis (eye inflammation), high blood pressure, diabetes, and heart disease.
“The findings from a large U.S. electronic database confirm that AS is more prevalent in whites as shown in previous studies, but the proportion of males and females between the two races is equal,” the authors wrote. “Both ESR and CRP were elevated in African American patients compared to white [patients], suggesting that the disease may be more severe in African Americans.”
The authors also pointed out previous research that showed that AS disease activity scores and functional impairment scores were much higher among Black people with AS than white or Latino.
“There are very few studies in literature of the racial determinants of disease outcome in AS. To our knowledge, our study is the first real-world population study to look at racial determinants of clinical features, disease activity, and comorbidities in AS in the United States,” the study authors wrote.
“The results demonstrate that despite low prevalence of AS in African American patients, African Americans tend to have elevated levels of markers of inflammation and anterior uveitis, and more comorbidities. An improved risk stratification and vigilance for early diagnosis and treatment of AS particularly in African American patients is needed.”
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Ankylosing Spondylitis. UW Medicine Orthopaedics and Sports Medicine.
Singh DK, et al. Racial Differences in Clinical Features and Co-morbidities In Ankylosing Spondylitis in the United States.” The Journal of Rheumatology. September 2019. doi: https://doi.org/10.3899/jrheum.181019.