January 29, 2021
According to a new analysis funded by the Centers for Disease Control and Prevention, about 204,295 Americans have systemic lupus erythematosus (SLE), based on strict criteria for diagnosis by the American College of Rheumatology. These data, however, do not include cutaneous lupus.
Based on an analysis of five studies, the national estimate was published this week in the professional journal Arthritis & Rheumatology. Because of the many challenges in diagnosing lupus, determining its prevalence has been difficult with existing estimates ranging from 161,000 to 1.5 million Americans.
Funded by the U.S. Centers for Disease Control and Prevention (CDC), researchers analyzed data from the CDC National Lupus Registry network of population based registries, focusing on diverse populations within four states and a fifth in the Indian Health Service. Using the American College of Rheumatology criteria to define systemic lupus erythematosus (SLE), they identified 5,417 cases in these five registries — which represents an average of 72.8 people per 100,000 people. Applying that number to the overall U.S. population of 330 million, they concluded that about 204,295 people in the country have SLE. This study did not include another form of lupus, cutaneous, which affects the skin.
Their analysis of the five registries confirmed that SLE is nine times higher for females than males. Prevalence was highest of all races and ethnicities among both females and males in the American Indian/Alaska Natives registry which was analyzed separately. It also revealed that SLE is most common among Black females, followed by Hispanic females, white females and Asian/Pacific Islander females. Results also showed that among males, prevalence was similarly highest among Blacks, followed by Hispanics, and Asian/Pacific Islanders. White males were least likely to have SLE.
Regional data analyzed were from Georgia, Michigan, California and New York. These areas were selected because they collectively represent large populations of Blacks, Asian/Pacific Islanders, and Hispanics – all groups previously thought to have a higher risk for SLE. American Indian/Alaska Natives were represented in the Indian Health Service registry.
Investigators concluded that this “coordinated network of population-based SLE registries provided more accurate estimates for SLE prevalence and numbers affected in the U.S.”
LRA Research Focus on Reasons Behind Disparity
The reason for this disproportionate effect on people of color remains a pressing issue. The LRA invests considerable resources to discover why lupus is more prevalent among women and people of color with approximately 10 grants in this area. Here are just three notable examples:
Patrick Gaffney, MD, Oklahoma Medical Research Foundation
Dr. Gaffney’s grant aims to uncover how race and ethnicity are linked to differences in the type of organ damage caused by lupus and identify new treatment targets.
John Mountz, MD, PhD, University of Alabama
Dr. Mountz found that patients with high levels of the molecule interferon beta (IFN-β) within their early developing (“baby”) B cells (the immune cells that grow to become autoantibody-producing cells) are more likely to have higher levels of autoantibodies and kidney disease. Among those individuals, African American patients, who are disproportionately affected by lupus, had higher levels IFN-β in these cells compared to Caucasian patients. Dr. Mountz is using his 2018 Distinguished Innovator Award to determine if the high level of IFN-β production within these baby B cells causes them to grow into adult autoantibody-producing B cells that trigger lupus.
Robert Hal Scofield, MD, The University of Oklahoma Health Sciences Center
Dr. Scofield’s grant is looking at whether having two X chromosomes, rather than the X and Y in men, brings along a double dose of genes that may predispose women to lupus. This insight will get us one step closer to understanding what causes this complex disease.
LRA Helping to Encourage Health Equity
The LRA also has long recognized the racial disparity this analysis confirms and continues to focus on alleviating the gaps in diagnosis and treatment of SLE for people of color.
Current projects include a collaboration with the National Kidney Foundation on an educational program for healthcare professionals to better diagnose, monitor and treat lupus nephritis. Information can be found here. In addition, the two groups recently conducted companion surveys of healthcare professionals and patients that uncovers a need for closer communication and coordination among treating physicians. Additional education and support materials will be developed in the coming year, to address critical gaps in knowledge identified by these surveys for both patients and healthcare professionals.
A long-term collaboration with the National Minority Quality Forum also aims to address disparities in healthcare. Together we are working on the Lupus Index, a project that is looking at Medicare and Medicaid data to help target our outreach education and lupus awareness efforts.