The researchers also looked at a subgroup of patients with lupus-related nephritis. However, these results remained too underpowered to demonstrate an association in that group after multivariable adjustment.
“In this very large study of Medicaid SLE patients drawn from a nationwide sample, we found a 31% and 22% increased risk for stroke among black and Hispanic patients [respectively] when compared with white patients,” Dr. Barbhaiya says. “The risk of heart attack was lower among Hispanics and Asians (39% and 43%, respectively) and similar for blacks when compared with whites. Although blacks had increased rates of hypertension, and Asians as well as Hispanics had fewer CVD risk factors compared with whites, adjustment for these factors did not account for the risks demonstrated.”
Results Need Confirmation
Dr. Barbhaiya says these results must be confirmed in other data sets using other populations. Additionally, as a population-based study, its ability to address individual patient management remains limited.
However, this large, Medicaid-based study did include SLE patients of multiple races and ethnicities, and it reveals demographic differences in CVD risks among SLE patients that clinicians should know about.
“The results go against current thinking, but are largely consistent with studies in the general population showing a Hispanic and Asian paradox,” Dr. Barbhaiya says. “It is currently not clear whether there is some protective element … causing them to not have as many strokes and MIs, or whether this is an epidemiologic association. However, this is the first time it has been shown in SLE.”
In contrast, African Americans have increased CVD risk factors, leading to more heart disease. The higher event rates in this group indicate SLE may result in an additional disease burden.
“If the MI risk [difference] is confirmed, this may suggest certain races/ethnicities could undergo earlier screening and aggressive risk factor management,” says Dr. Barbhaiya. “Additionally, we did not look at age stratification in this study. Further research is needed to determine whether, for example, we should be screening for hypertension and cholesterol in younger blacks with SLE than suggested by current guidelines.”
The fact the study worked with such a large data sample—a decade of data on more than 65,000 SLE patients—bolsters its results. Sociodemographic factors, as well as CVD- and SLE-specific comorbidities, were available in the claims data. This allowed the researchers to fit several models looking for confounders and mediators that might have contributed to increased CVD deaths in these patients.
