Mortality from systemic lupus erythematosus has declined since 1968 in the United States, but not as markedly as rates of death from other causes, according to a study in Annals of Internal Medicine.
Furthermore, systemic lupus erythematosus (SLE) mortality varied significantly by sex, race, and geographic region, noted Eric Y. Yen, MD, and his associates at the University of California, Los Angeles. Mortality from SLE was highest among females, black individuals, and those who lived in the South. Multivariable analyses confirmed that sex, race, and geographic region were independent risk factors for SLE mortality and that race modified relationships among SLE mortality, sex, and geographic region.
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Between 1968 and 2013, there were 50,249 deaths from SLE and more than 100.8 million deaths from other causes in the United States, the researchers said. Mortality from other causes continuously dropped over the study period, but SLE mortality dropped only between 1968 and 1975 before rising continuously for 24 years. Only in 1999 did SLE mortality begin to fall again. Consequently, the ratio of SLE mortality to mortality from other causes rose by 34.6% overall between 1968 and 2013, and rose by 62.5% among blacks and by 58.6% among southerners.
After the researchers accounted for age, sex, race or ethnicity, and geographic region, the risk of death from SLE dropped significantly during 2004 through 2008, compared with 1999 through 2003, and declined even more between 2009 and 2013. Female sex, racial or ethnic minority status, residing in the South or West, and being older than 65 years all independently increased the risk of dying from SLE.
Although the South had the highest SLE mortality among whites, the West had the highest SLE mortality among all other races and ethnicities, the investigators determined. Previous research has identified pockets of increased SLE mortality in Alabama, Arkansas, Louisiana, and New Mexico, and has shown that poverty is a stronger predictor of SLE mortality than race, they noted. “Geographic differences in the quality of care of patients with lupus nephritis have also been reported, with more patients in the Northeast receiving standard-of-care medications,” they wrote. “Interactions between genetic and non-genetic factors associated with race/ethnicity and geographic differences in environment, such as increased sunlight exposure, socioeconomic factors, and access to medical care, might also influence SLE mortality.”
The National Institutes of Health, the Lupus Foundation of America, and the Rheumatology Research Foundation funded the study. The investigators reported having no conflicts of interest.