Background SLE is a chronic disease that affects many organ systems and can cause permanent damage. We sought to determine if there are differences in patterns of SLE organ system damage among racial/ethnic groups.

Methods Data derive from the baseline visit of the California Lupus Epidemiology Study (CLUES), an ongoing cohort of patients in the San Francisco Bay Area with confirmed SLE diagnoses. Participants provided access to medical records and had a visit with a study rheumatologist. Race/ethnicity (White, African American, Hispanic of any race, and Asian) was determined by patient report. Due to the small sample size, patients from other racial groups were excluded from this analysis (n=5). Disease damage was measured using the SLICC/ACR Damage Index (SDI), calculated at the study visit. We examined damage at the organ system level, using items from the SDI, and defined glucocorticoid-related damage as avascular necrosis, diabetes, cataracts, and osteoporosis. Logistic regression was used to estimate the prevalence of damage in each organ system and the prevalence of glucocorticoid-related damage by race/ethnicity controlling for current age. We ranked the prevalence of damage in each organ system that comprises the SDI for each racial/ethnic group.

Results Among 323 participants, 89% were female, 39% Asian, 11% African American, 22% Hispanic of any race, and 29% White. Mean age was 45±14; mean age at diagnosis 29±12. SDI ranged from 0 to 10 points, mean 1.8±2.0; 70% of the cohort had SDI>0. There were no differences in mean SDI by race/ethnicity (p=0.4; see Table). Musculoskeletal and ocular damage were among the five most common systems for all groups. African Americans were significantly (p=0.02) more likely to have skin damage than the other racial/ethnic groups. Non-Hispanic whites were the only group that had malignancy in their top five systems of SDI damage. Renal damage was most prevalent among Hispanics and least prevalent among whites. Glucocorticoid-related damage was more prevalent among African Americans in comparison to whites, although this difference was not statistically significant.

Conclusions There are differences in prevalence of damage by organ system among racial/ethnic groups, with blacks significantly more likely to have skin manifestations and whites more likely to have a history of cancer. There is also evidence of higher glucocorticoid-related damage among blacks. Further research is required to explain what leads to these differences; they could be related to quality and access to care and treatment, or to differential disease biology or environmental exposures.

Funding Source(s): CDC (U01 DP005120)