Background Epidemiologic data on systemic lupus erythematosus (SLE) are limited, particularly for racial/ethnic subpopulations in the United States (U.S.). This meta-analysis leveraged data from the Centers for Disease Control and Prevention (CDC) National Lupus Registry network of population-based SLE registries to estimate the general and by sex, race/ethnicity incidence of SLE in the U.S.

Methods The CDC registries were established in Michigan, Georgia, California, New York and through the Indian Health Service (IHS). Registries used the 1997 revised ACR classification criteria for SLE as their case definition, and the surveillance time periods ranged from 2002-2009. Age-standardized incidence rates were stratified by sex and race/ethnicity from the state-based registries; the American Indian/Alaska Native (AI/AN) estimate was based only on the IHS registry that covered multiple states. For pooling data across the four sites with data on different racial/ethnic groups, we used Cochran’s Q and I² statistic to test for heterogeneity across sites. Due to significant heterogeneity, we used a random effects model to calculate pooled incidence, which allows for more variation across sites. We then extrapolated to the 2018 Census population data according to sex and race-stratified groups, including data from the IHS registry, and summed the stratum-specific estimates to provide a total population estimate of incident SLE cases in the U.S.

Results The registries contributed 1,057 classified cases of SLE from a mix of urban and rural areas. From the meta-analysis of the four state-based registries, the overall incidence was 5.1(95%CI4.6,5.6) per 100,000 person-years. The incidence among females was about 7 times higher than males (8.7 vs 1.2). In the meta-analysis, the incidence rate was highest among Black females (15.9,95%CI12.5,20.3), followed by Asian/Pacific Islander females (7.6,95%CI5.5,10.4), Hispanic females (6.8,95%CI6.2,7.6), and White females (5.7,95%CI4.9,6.7). Among males, the incidence rate was highest among Black males (2.4,95%CI1.8,3.0) followed by Hispanic males (0.9,95%CI0.4,1.9), White males (0.8,95%CI0.6,1.1), and Asian/Pacific Islander males (0.4,95%CI0.2,0.6). The AI/AN incidence estimates, had the second highest rates of SLE among females (10.4,95%CI6.6,14.6) and highest for males (3.8, 95%CI1.6,7.8). Applying our sex- and race-specific incidence estimates to the corresponding population denominators from 2018 Census data, we estimated that 14,263 new persons (12,560 females and 1,703 males) in the U.S. were diagnosed with SLE and fulfill the ACR classification criteria, table 1.

Conclusion A coordinated network of population-based SLE registries provided more accurate estimates of the incidence of SLE and the numbers of new individuals affected with SLE in the U.S. in 2018.