Population-Based Incidence and Prevalence of Systemic Lupus Erythematosus: The Michigan Lupus Epidemiology and Surveillance Program

Background: We estimated the incidence and prevalence of systemic lupus erythematosus (SLE) in a sociodemographically diverse southeastern Michigan source population of 2.4 million. Methods: SLE cases fulfilling American College of Rheumatology classification criteria (primary case definition) or rheumatologist-judged SLE (secondary definition) and residing in Wayne or Washtenaw Counties, 2002-2004 were included. Case finding was performed from 6 source types, including hospitals and private specialists. Age-standardized rates were computed, and capture-recapture performed to estimate case under-ascertainment. Results: Overall age-adjusted incidence and prevalence (ACR definition) per 100,000 were 5.5 (95% CI 5.0, 6.1) and 72.8 (95% CI 70.8, 74.8). Among females, incidence was 9.3/100,000 and prevalence was 128.7/100,000. Only 7 cases were estimated to have been missed by capture-recapture, adjustment for which did not materially impact rates. SLE prevalence was 2.3-fold higher in blacks than whites, and 10-fold higher in females than males. Among incident cases, mean age (±SD) at diagnosis was 39.3±16.6 years. Black cases had a higher proportion of renal disease and end-stage renal disease (40.5% and 15.3%) versus white cases (18.8% and 4.5%); blacks with renal disease were diagnosed with SLE at younger age [(34.4±14.9) vs whites (41.9±21.3); p=0.05]. Conclusions: SLE prevalence was higher than described in most other population-based studies, and reached 1 in 537 among black females. There were substantial racial disparities in the burden of SLE, with blacks compared to whites experiencing earlier age of diagnosis, more than 2-fold increases in SLE incidence and prevalence, and increased proportion of renal disease and progression to ESRD. © 2013 American College of Rheumatology.