Ethnic disparities in dermatomyositis mortality

Summary: Abstract Body: Recent reports have highlighted potential ethnic differences in the presentation and clinical course of dermatomyositis (DM), but mortality data of non-White groups with DM is limited. This retrospective, single-center study presents a review of DM mortality in a diverse patient cohort. Patients seen at UC Irvine Medical Center between Jan 2016 and Dec 2024 with adult-onset DM meeting ACR/EULAR criteria within this timeframe were included. Fisher’s exact test and Log-rank test for hazard function analysis were performed. Of the 91 patients identified, 36.2% (33/91) were Non-Hispanic White, 36.2% (33/91) were Hispanic, 24.2% (22/91) were Asian, and 3.3% (3/91) were African American/Black. Documented dates of death were found in 10 of the 91 patients, wherein 60% (6/10) were Asian, 20% (2/10) were Hispanic, and 20% (2/10) were White. Log-rank tests demonstrated higher mortality rates in Asian patients compared to White (p=0.008) and Hispanic (p=0.02) counterparts. Mortality for Asian patients was significantly higher within one year of diagnosis compared to White and Hispanic counterparts (p=0.02). Malignancy was the cause of death for 100% (2/2) of Hispanic patients, 67% (4/6) of Asian patients, and 50% (1/2) of White patients. TIF1-γ was positive in 50% (5/10) of the deceased patients; 3 of these 5 patients were Asian. Autoantibody profiles in DM may vary across ethnicities and are strongly associated with clinical subtypes, such as MDA5 with ILD and TIF1-γ with malignancy. While ILD is recognized as a significant cause of mortality in MDA5+ DM, particularly among Asian patients, we found that our Asian patients cohort experienced higher mortality rates primarily due to TIF1-γ+ DM associated malignancies, rather than MDA5+ ILD. These findings may represent emerging trends that warrant further investigation. In summary, this study suggests differences in mortality rates across ethnicities and highlights the importance of assessing autoantibodies as predictors of disease outcomes. Validation in larger cohorts is needed to better understand these relationships and improve patient management. Jack Woll¹, Ellee P. Vikram¹, Michelle S. Min¹ 1. University of California Irvine Department of Dermatology, Irvine, CA, United States. Minoritized Populations and Health Disparities Research