The research provides the first national estimate of how widespread the auto-immune disease is, including its prevalence in certain ethnic groups. Overall, a total of 204,295 people had lupus in 2018 in the United States, according to the study published this month in the journal Arthritis & Rheumatology. For every 100,000 people in the population, there were 72.8 cases of lupus. Lupus rates were 9 times higher for women compared with men, at 128.7 versus 14.6 per 100,000 people; and highest among American Indian, Black, and Hispanic women, at 270.6, 230.9, and 120.7 cases per 100,000 people. There were 84.7 cases of lupus per 100,000 white women. Anecdotally, there was a common perception that the risk of lupus tends to be higher in certain groups, but the concrete data was very sparse, says the study’s senior investigator, Emily Somers, PhD, associate professor and epidemiologist at the University of Michigan. “This is the first time there was a dedicated public health initiative to look at rates of lupus in the population.” The new data is the culmination of two decades of work. In 2002, Dr. Somers along with researchers across the country worked with the Centers for Disease Control and Prevention (CDC) to set up four state registries to track lupus rates in Georgia, Michigan, California, and New York. They set up a fifth registry with the Indian Health Service. Before these registries were set up, researchers estimated lupus rates by extrapolating from a patchwork of smaller studies. However, previous estimates were misleading because different methodologies were used, lupus was defined in different ways, and the research was done in predominantly white populations, Somers says. The registries for this new effort used identical American College of Rheumatology (ACR) classification criteria for identifying lupus cases. The researchers analyzed records for 5,417 adults and children diagnosed with lupus since 2002 at all of the state registries for the disease. They then calculated the number of people with lupus for every gender and ethnic group and applied those demographic numbers to 2018 U.S. Census population statistics. The study also quantified, for the first time, the prevalence of lupus in men with direct comparisons between ethnic groups. Lupus rates were highest in Black men, followed by Hispanic, Asian, and white men. Somers says the research also found the ethnic groups at a higher risk of lupus tend to have onset of the disease at a younger age, and with more disease severity. “This was the first step into gathering more reliable, detailed data on the issue, using a standardized way of defining cases,” Somers says. “It’s important to have a firm understanding of baseline rates of this disease to flag trends in the population and how they’re changing over time.” RELATED: 5 Things Selena Gomez’s Battle With Lupus Has Taught Us About the Autoimmune Disease
More Research Needed to Answer Why Disparities Exist
The research community has theories as to why there are such stark disparities in lupus rates between genders and race, but there is no “home run answer” to this important question, according to the study’s lead author, Peter Izmirly, MD, associate professor and rheumatologist at New York University in New York City. He says some of the registries have already received subsequent funding to study this. “We will try to answer these questions, exploring genetic, immunological, biological, and environmental reasons that may be contributing to [the differences in rates],” he says. Lupus, or systemic lupus erythematosus (SLE) is an autoimmune disease, meaning the body’s own immune system doesn’t function property and attacks you by mistake, affecting multiple organs throughout the body. It’s a lifelong, chronic disease, but symptoms and their severity vary from patient to patient. About 70 percent of people diagnosed with lupus have SLE. In these cases, the disease is mild and may cause a rash, joint pain, or inflammation of the kidneys among other complications. RELATED: Speaking Lupus: A Glossary of Terms Used to Describe Symptoms, Complications, Tests, Treatments, and More Because the disease appears in such different ways, diagnosing and developing treatment have been longstanding challenges. Benlysta, or belimumab, is the single drug therapy approved specifically for treating lupus, but some evidence suggests it may be less effective in Black people with lupus, Somers says. “Hopefully, the data we’re generating now can help make the case for prioritizing and emphasizing focus on the groups that are in greatest need, making sure resources are adequately addressing them,” Somers says.
New Data Could Reclassify Lupus as Rare Disease
With the new study estimating that just over 200,000 Americans suffer from SLE, lupus could be officially reclassified as a rare disease under the U.S. Rare Diseases Act. This is a pivotal shift that could make drug development easier for pharmaceutical companies trialing potential lupus therapies. A rare disease classification would decrease the number of study participants needed for testing new treatments and shaping the design of clinical trials. “Now that we have the numbers to know that lupus is a rare disease, we can underscore the point that it is a challenge to enroll large numbers in a trial. If we’re looking at personalized medicine and therapies targeted at subsets of lupus, then these subsets are even more of a rarity,” Somers says. Overall, the researchers hope their latest findings can help to shape how frontline doctors screen for the disease and increase outreach to communities most susceptible to lupus. Diane Gross, national director of advocacy and programs at the Lupus Research Alliance (LRA), says the data will indeed help these efforts, which are focus areas for the LRA “It starts in the doctor’s office. We need to educate frontline doctors, and patients, to pay attention to these symptoms and to understand that women — and women of color in particular — have a much higher incidence of lupus,” Gross says. The LRA leads outreach efforts in Black, Indigenous, and People of Color (BIPOC) communities that are at highest risk of lupus, from making them aware of the higher prevalence of the disease to encouraging more participation in clinical trials. Gross said the data can help to ensure there are enough rheumatologists in regions with populations at high risk for lupus. The LRA works with other organizations, including the National Kidney Foundation on educational programs to help doctors better diagnose, monitor, and treat lupus nephritis (a subtype of SLE that affects the kidneys). This more accurate incidence data will help inform these efforts, Gross says. The more comprehensive data on lupus rates in the United States will improve research efforts, too, says Ali Duarte Garcia, MD, a rheumatologist at Mayo Clinic who was not involved in this latest research, but is a recent recipient of CDC funding to carry this lupus research forward. “Now we can look closer at patients’ experiences with lupus and how the disease evolves,” Dr. Duarte Garcia says. His ongoing work with the CDC will consider lupus patients’ access to healthcare, pain management, the prevalence of disability, the severity of the disease, and mortality and survival rates based on the data from these registries.
