Multi-organ Involvement More Common in Asian, Hispanic Patients With SLE

Hispanic and Asian patients face a heightened risk of renal, hematologic, and multi-organ involvement following a diagnosis of systemic lupus erythematosus (SLE), according to a new analysis of more than 300 patients representing multiple racial and ethnic groups.

The study also showed that multi-organ involvement was generally common, with nearly one-third of the entire cohort reporting it. The study was published in the journal Arthritis Care & Research.

Existing research has shown that certain racial and ethnic groups are disproportionately affected by SLE, but the new report’s investigators wrote that data looking specifically at associations between race and ethnicity and the disease’s manifestations in particular organs (or multiple organs) is limited. What data there is suggests that non-White patients often have more abrupt onset of SLE manifestations, noted the authors, including corresponding author Alfredo Aguirre, MD, of the University of California, San Francisco.

Aguirre and colleagues wanted to gain a better sense of how race and ethnicity affected the risk of particular disease courses in patients with SLE, so they examined data from the California Lupus Epidemiology Study (CLUES), a longitudinal study of patients with SLE. The database yielded 326 participants, most of whom were female (89%), and who represented a variety of racial and ethnic groups. Among the sample, 30% were White, 23% were Hispanic, 11% were Black, and 36% were Asian. The patients had an average age of 45 years and an average age at SLE diagnosis of 29 years.

The investigators classified cohort participants based on organ involvement, including those with multi-organ involvement (which was defined as having disease manifestations in at least 2 distinct organ systems). The authors used Kaplan-Meier curves and Cox proportional hazard regression to compare outcomes among the groups.

The data showed that renal and hematologic involvement were most likely to happen early in the disease course of SLE, while neurologic and cardiovascular manifestations tended to come later. The analysis also showed, however, that race and ethnicity correlated with whether and when those manifestations occurred.

“Following SLE diagnosis, Hispanic and Asian patients experienced a two-to-threefold higher rate of renal and hematologic disease compared to White participants,” Aguirre and colleagues wrote. “In addition, Hispanic and Asian patients developed these manifestations sooner after SLE diagnosis.”

The analysis also showed that Hispanic patients were more than 3 times as likely to have multi-organ involvement compared to White patients, and Asian patients were 2.5 times as likely to have multi-organ involvement, compared to White patients.

The study found Asian patients had a heightened risk of end-organ manifestations, though the authors said other studies have found different results. They noted that the majority of their Asian cohort self-identified as Chinese or Filipino, so it is possible that their outcomes are not generalizable to all Asian individuals.

Broadly speaking, Aguirre and colleagues said their study represents a significant step forward in the goal of better identifying patients who are at risk of severe disease trajectories. They added that they were struck by the racial and ethnic disparities in terms of multi-organ involvement. While just 21% of White patients had multi-organ disease, 32% of Asian patients had the same, as did 39% of Hispanic patients.

“The causes of these disparities in SLE disease presentation are multifactorial and complex, and additional studies will be needed to investigate the contributions of social and biological factors leading to disparate disease outcomes,” the authors wrote.

They said possible factors could be access to care, treatment adherence, poverty, and racial discrimination, among others. However, they said genetic predispositions also play a role.

What is clear, they said, is that sufficient gaps exist in outcomes among these groups to warrant further study.

Reference

Aguirre A, Izadi Z, Trupin L, et al. Race, ethnicity, and disparities in risk of end-organ lupus manifestations following SLE diagnosis in a multiethnic cohort. Arthritis Care Res (Hoboken). Published online April 22, 2022. doi:10.1002/acr.24892