Disparities in AS Diagnosis and Treatment

Medically Reviewed by Carol DerSarkissian, MD on July 31, 2022
4 min read

Ankylosing spondylitis (AS) is a type of arthritis that causes joint inflammation and back pain and stiffness. Though it’s thought to be most common in white men, the disease also affects women and Black people. And when it does, it may be more serious. It may also be more likely to be overlooked.

This scenario isn’t specific to AS. Minorities and people with lower incomes also tend to receive delayed or inferior care for other conditions, like heart disease, diabetes, AIDS, and cancer. These differences in health outlooks between specific populations of people are called disparities. Experts believe a variety of things are to blame for the inconsistencies in care.

There’s no cure for AS, but certain treatments and lifestyle habits can help lessen pain and improve outcomes. If the disease is missed or a diagnosis is postponed, as it sometimes is in Black people and women, treatment could be delayed, and your quality of life can suffer.

It’s often hard for anyone to get an accurate AS diagnosis, since its main symptom – back pain – is so common and has many causes. But racial, gender, and socioeconomic disparities make this process even more challenging.

Doctors don’t know exactly how many people live with AS. But estimates show that between 0.9% and 1.4% of adults in the United States have the condition.

Historically, researchers thought AS mostly affected men. But recent research has suggested that it’s often under-recognized or misdiagnosed in women. One study found that, on average, women wait about 8.8 years for an AS diagnosis while men wait about 6.5 years.

In a 2021 study that included more than 700,000 military service members, researchers found that rates of AC didn't differ much between women and men. “Our findings suggest that sex may not predict AS incidence in the U.S. population,” the study authors wrote.

With regard to race, AS is more likely to affect white people than Black people. In fact, some older research shows the disease is three times less common in Black Americans as in white ones. It’s very rare in Black Africans with unmixed ancestry.

About 9 out of 10 people with AS carry a certain gene variation, or variant, called human leukocyte antigen B27 (HLA-B27). Black people are much less likely to have this gene variant than white people. Studies suggest that 8% of white people and 2%-4% of Black Americans carry HLA-B27.

Though AS is less common in Black Americans, research indicates that it’s more serious in this population. Studies show Black Americans tend to have more signs of bodywide inflammation and higher rates of eye inflammation (anterior uveitis). They’re also more likely to have other health issues that go along with AS, such as high blood pressure, diabetes, depression, and heart disease. Additionally, AS seems to take a greater toll on quality of life for Black American women.

Women, in general, may have more active disease because of a delay in diagnosis or a misdiagnosis. That’s likely because it often gets caught later, and treatment isn’t started promptly. AS is tougher to treat when it’s not found until it has already progressed.

AS symptoms are very similar in men and women. But joint damage doesn’t show up on X-rays in women as often as it does in men, so problems can be harder to spot. Studies also show that women may not respond as well to TNF inhibitors, medicines commonly used to treat AS.

In one study, researchers found 20.7% of women with AS were misdiagnosed with fibromyalgia, compared with 6.6% of men.

Studies have also shown that lower socioeconomic status is associated with worse AS outcomes. Those with lower social and economic status are likely to have more serious AS and it tends to have more consequences in their lives.

Disparities in outcome among women, people of color, and low-income people could be the result of late diagnosis and treatment and/or other causes.

The fact that the disease tends to be more serious in Black people is thought to be partly due to genetics. Experts believe social, cultural, and economic factors play a role, too. One small study suggested that racial discrimination may trigger an inflammatory response in Black people, especially in those with compromised immune systems.

A review study found that discrimination based on race or ethnicity contributes to chronic diseases and poor physical and mental health.

Other social factors that may contribute to poorer health outcomes for Black Americans include:

  • Lack of medical insurance
  • Lack of affordable housing
  • Food insecurity

Researchers are still trying to understand how ethnicity, race, gender, and social status affect people with AS. That’s why it’s important for women and people of color to participate in clinical studies.

What we know is that Black Americans, women, and those with a low socioeconomic status seem more likely to have serious cases of AS. There are probably many things that contribute to this health disparity.

Identifying AS earlier in these groups is important for prompt treatment and a better outcome. If you think you may have AS or another inflammatory condition, don’t give up on getting an accurate diagnosis. It might take longer than you’d like, but be sure your pain is addressed. The sooner you can start treatment, the better.