Systemic lupus erythematosus more severe among US Asian population than whites

Systemic lupus erythematosus is more severe among U.S. Asian populations compared with whites, with Filipino individuals in particular affected at “strikingly” young ages, according to findings published in Arthritis Care & Research.

“Systemic lupus erythematosus (SLE) is a complex chronic condition that disproportionately affects racial/ethnic minorities,” Kimberly DeQuattro, MD, of the University of California, San Francisco, and colleagues wrote. “International multiethnic cohorts have found that SLE patients with Asian ancestry tend to have younger age at diagnosis, more frequent autoantibody positivity as well as worse disease activity, organ-specific and overall damage and SLE severity as compared with whites.”

“There are outcomes for which there is no evidence that Asians differ from whites at follow up, such as with overall damage,” they added. “These findings are largely consistent with Asia-specific studies that investigate differences in genetic expression and other outcomes among Asian patients with SLE. Importantly, new large-scale prospective registries are evaluating the impact of SLE across the Asian subgroups and in comparison to non-Asian counterparts. There is a gap in knowledge about how SLE affects U.S. Asians.”

To analyze SLE disease activity, severity and damage among patients of Asian ancestry in the United States, DeQuattro and colleagues examined data from the California Lupus Epidemiology Study (CLUES). According to the researchers, CLUES contains data from the California Lupus Surveillance Project, which used outpatient, hospital and laboratory records to identify all SLE patients residing in San Francisco City and County from 2007 to 2009. In addition, CLUES included patients from the nine counties of the San Francisco Bay Area from 2015 to 2018, via academic and community rheumatology clinics as well as existing local research cohorts.

Kimberly DeQuattro

In all, the CLUES cohort included 328 individuals. Asians were the largest racial/ethnic group, at 38%. Among the entire cohort, 22% identified as Chinese and 9% identified as Filipino. Researchers collected data in English, Cantonese, Mandarin and Spanish, using validated measures for disease activity — the Systemic Lupus Erythematosus Disease Activity Index — disease severity — the Lupus Severity Index (LSI) — and damage — the Systemic Lupus International Collaborating Clinics Damage Index. They then analyzed differences in outcomes among racial/ethnic groups using multivariable linear regression.

According to the researchers, the average age at SLE diagnosis was younger among Asian patients, at 27.9 years, compared with 29.4 years for whites and 34 years for Black patients. The average age at diagnosis was particularly young among Filipino patients, at 22.2 years. Early age at diagnosis was associated with greater organ damage among Asian, Black and Hispanic patients, but not among white patients.

In addition, SLE disease severity was significantly higher among Asian patients, with an LSI of 7.1, compared with 6.5 among whites (P < .05). LSI figures were similar between Asian, Black and Hispanic patients. Disease activity and damage were not significantly different across any racial/ethnic groups.

“We found that U.S. Asians, primarily Chinese but especially Filipinos, demonstrated earlier age at diagnosis and higher disease severity as measured by LSI than whites,” DeQuattro and colleagues wrote. “Increased vigilance among clinicians caring for Asians with SLE may detect more severe disease earlier in this group of patients, which could improve outcomes. Further defining unique disease patterns, genetic influences and treatment responses among Asian subgroups may help to identify patients at greatest risk for disability and death.”