Photo Credit: Andrey Popov

New research suggests patients with psoriatic arthritis may experience the disease differently depending on their race and ethnicity.

A recent study published in Rheumatology showed that psoriatic arthritis (PsA) disease activity and symptom severity were different for non-White and White patients.

“Individuals of racially and ethnically diverse backgrounds are underrepresented in PsA research/clinical trials, despite evidence that their disease presentation, severity, and course may be distinct,” wrote Rebecca H. Haberman, MD, and colleagues. To build on existing literature, they investigated how patient race and ethnicity might impact PsA phenotypes and disease activity.

Physician’s Weekly (PW) spoke with Dr. Haberman to learn more about the findings and how HCPs can account for patient demographics when diagnosing and treating PsA.

PW: What inspired your research into race and ethnicity’s associations with PsA?

Dr. Haberman: Historically, and of common knowledge, PsA and psoriasis are thought of as diseases that affect White individuals. Even in clinical trials, a lot are comprised of more than 90% White individuals. However, I work in New York City, where we see a diverse set of patients, so we knew this assumption was not true in day-to-day rheumatologists’ clinical practice.

Given the large, diverse patient population, we wanted to look at the potential differences in PsA presentation, disease activity levels, and comorbidities since this is not widely available in the literature.

Can you walk through some of the major findings?

Our study is an observational study of the patients we see at the NYU Psoriatic Arthritis Center and some of our affiliated practices and clinics. We looked at 817 patients and found that about one-quarter of our patients were non-White. While this does not sound like a lot, compared with existing studies, it is a significant proportion of patients.

We found that non-White individuals had more tender joints, even though they had similar swollen joint counts and similar levels of medication use, which tells us they may be experiencing their disease differently. Non-White patients also had higher levels of radiographic axial disease.

We had a high number of Hispanic individuals, so we were able to look at that group specifically. We found that people who were Hispanic were more likely to have higher tender joint counts and higher RAPID3 scores. Compared to non-Hispanic White individuals, Hispanic patients were also more likely to have moderate or severe psoriasis rather than mild psoriasis.

In addition, we found that non-White individuals with PsA are more likely to have cardiovascular comorbidities.

How can these findings inform rheumatologists’ everyday clinical practice?

I think the most important thing is to recognize PsA in your non-White patients because often, rheumatologists are not looking for it or thinking about it. This is especially important because psoriasis may look different in people of non-White skin color. Patients may not have that classic erythematous scale shown in textbooks. If a rheumatologist is unsure what a rash is, send the patient to a dermatologist and ensure it is not psoriasis before writing it off.

People may experience PsA differently, especially in terms of axial disease. We often think about axial disease as a disease of White individuals because it is associated with the genetic marker HLA-B27, which is more common in White individuals. We may dismiss people’s back pain as unrelated to their PsA, but our study shows it may be related.

What would you like to see future PsA research explore?

You cannot group people into White and non-White. Even within our group of patients who are Hispanic, there is a lot of variability. In our group of patients who are Asian, there is a lot of variability. So, one goal is to have much larger cohorts.

Race is not an isolated factor. There is also the experience of race and socioeconomic factors. We must do a better job at delineating what may be clinical socioeconomic factors versus the biologic factors of race and ethnicity. We must collect much more information about lifestyles, education levels, income levels, and other socioeconomic factors and do sampling—for example, taking blood from patients to look at their immune and complete genetic profiles. Dig deeper into both the genetics and the biological factors, as well as the clinical factors, driving the differences between patients of all different races and ethnicities.

Is there anything else that you would like to add?

In this study, we also looked at women versus men who have psoriatic arthritis and found that women experience their disease differently. While men and women had similar inflammation and joint swelling, women had much higher RAPID3 scores and tender joint counts. Many factors, not just race and ethnicity, play a role in these differences.