Health Disparities: AxSpA Is Not Just A White Person’s Diagnosis
A common misconception is that axial spondyloarthritis (AxSpA) only affects white people. It is true that white people are more likely to be diagnosed with AxSpA. But this may not mean that people of color are less likely to develop AxSpA. It may just be biased by diagnosis methods.
White people are more likely to be positive for HLA-B27. This is a protein biomarker used to diagnose AxSpA. But not every person with AxSpA is positive for HLA-B27. So people of color with mild AxSpA may be more likely to get misdiagnosed.
Plus, people of color experience more severe AxSpA symptoms than white people. Experts say genetic, social, and economic factors likely cause this trend. However, we need more research to understand and address this inequality.
The misconception about AxSpA and ethnicity
Researchers have studied how ethnicity is related to AxSpA diagnosis. One report in 2012 analyzed 5,000 American adults. It showed that white Americans are almost twice as likely as black Americans to satisfy criteria for AxSpA.1,2
Another study in 2016 examined 2,500 people across the world with chronic back pain. Of this group, more people from Europe met the criteria for AxSpA than people from Africa or Latin America.3
Experts say this may be caused by differences in HLA-B27 status. Non-Hispanic white Americans are more likely to be HLA-B27 positive than other Americans.4,5 And people from Europe are more likely to be HLA-B27 positive than people from Africa or Asia.3
This can be interpreted in different ways. The first is that white people are more likely to develop AxSpA because they have higher levels of HLA-B27. However, people who are HLA-B27 negative can still develop axSpA. And compared to HLA-B27 positive people, they experience a longer diagnosis delay.6
So another interpretation is that people of color with AxSpA could be more likely to get misdiagnosed because of their HLA-B27 status. Or they may not be diagnosed until the disease progresses further. If this is the case, then white people are not more likely to develop axSpA. They are just more likely to be properly diagnosed.
Most studies on AxSpA in people of color are too small to make definite conclusions. We need much more data to explain why white people are diagnosed with AxSpA more often.
Ethnicity and AxSpA severity
Researchers have also compared AxSpA severity between American ethnic groups. In general, African Americans experience more severe AxSpA symptoms than white Americans.
A study in 2017 of almost 1000 people with axSpA showed this trend. The data shows that African Americans have greater functional impairment and higher disease activity than white or Latino Americans.1
Another report published in February 2020 showed this in a group of over 10,000 people with AxSpA. The data shows that African Americans have higher erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels. These markers indicate increased inflammation.5
African Americans with axSpA are more likely to have additional diseases. This includes high blood pressure, diabetes, and depression.5
Addressing AxSpA racial disparity
It is clear that African Americans experience more severe AxSpA despite being diagnosed less often. But we do not yet know the reason for these trends.
One reason could be that we are missing mild AxSpA cases in African Americans. This may be due to HLA-B27 status. And there is decreased suspicion of AxSpA for African Americans. Missing these mild cases may cause longer diagnosis delays and worse disease outcomes.
And other cultural, social, and economic factors also play a major role. We must have health policies that address the increased AxSpA severity experienced by African Americans. To do this, we need more research to understand this trend.
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