AxSpA Effects May Be More Severe for Black Patients

Marcia Frellick

May 24, 2023

CLEVELAND – Documenting the prevalence of axial spondyloarthritis (axSpA) among Black Americans has been difficult because of little published data, but new research suggests that when Black Americans do have the disease, it seems to be more severe.

Iman Abutineh, MD, of the University of Tennessee, Memphis, discussed her team's work at the annual meeting of the Spondyloarthritis Research and Treatment Network (SPARTAN).

A total of 244 patients with axSpA were identified, including 168 (69%) males, 78 (32%) Black patients, and 143 (59%) White patients.

Average age of onset for patients overall was 27.7 years, and age at diagnosis was 36.1 years with a 7-year delay in diagnosis. Sixty-six (27%) patients had nonradiographic axSpA, 83% were on tumor necrosis factor inhibitors, and 38% were prescribed glucocorticoids.

The researchers found several differences by race.

White patients were more likely to be HLA-B27 positive (77% vs. 59%; P = .010). White patients also had higher prevalence of psoriasis, coronary artery disease, and family history of SpA. White females had a higher prevalence of inflammatory bowel disease, fibromyalgia, depression, and lower grades of sacroiliitis.

Black patients had more hip involvement

A higher percentage of Black patients had elevated erythrocyte sedimentation rate (ESR), C-reactive protein (CRP), and hip involvement. In comparing hip involvement, the researchers found that 39 (39%) White males had hip involvement as did 9 (21%) White females. In comparison, 22 (45%) Black men in the study and 14 (54%) Black women showed hip involvement (P = .035).

After adjustment for age, sex, HLA-B27, and insurance status, Black patients had higher grades of sacroiliitis with an odds ratio of 2.32 (95% confidence interval, 1.23-4.44). Black patients had a numerically longer delay in diagnosis, compared with Whites (7.93 vs. 6.64 years), but this did not achieve statistical significance (P = .454), the researchers wrote.

Study addresses racial disparities

"Traditionally we think of axial spondyloarthritis largely in Caucasian males who are HLA-B27 positive," Dr. Abutineh said, "and we found that there is still a significant portion of patients who don't meet the criteria that do have disease that is very significant."

Although actual prevalence was not clear from this study, Dr. Abutineh said their data suggest a 3-to-1 ratio of White-to-Black patients with spondyloarthritis, "but of the Black patients who are diagnosed, their disease is almost always more severe. That points to why it's important to have a high index of suspicion for this disease in that patient population because if you miss it, it could be detrimental to the patients."

Swetha Alexander, MD, a rheumatology fellow at the University of Utah, Salt Lake City, who was not part of the study, said in an interview, "It is an excellent and timely study addressing the racial disparities and inequities surrounding axSpA diagnosis. It highlights the delay in diagnosis and increased burden of disease among Black Americans."

She said the study may prompt a further look into barriers to care for Black Americans and their beliefs regarding seeking health care for their pain.

Higher rates of nonradiographic axSpA among Black patients

The rate of nonradiographic axSpA among Black Americans was more than twice that of their White counterparts, which, Dr. Alexander noted, could make it more difficult to diagnose axSpA in that population.

The odds ratio for Black patients having nonradiographic axSpA, compared with Whites, was 2.265 (95% CI, 1.082-4.999; P = .035), after adjustment for age, sex, and HLA-B27 status.

Adult patients with axSpA were identified from rheumatology clinics at four major hospital systems and one private clinic in Shelby County, Tenn., between 2011 and 2021. Patients met modified New York (mNY) or Assessment of Spondyloarthritis International Society (ASAS) criteria as assessed by reviewers.

The authors and Dr. Alexander reported no relevant financial relationships.

This article originally appeared on MDedge.com, part of the Medscape Professional Network.

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