Black patients with systemic lupus erythematosus (SLE) are known to have significantly elevated risk for stroke and ischemic heart disease (IHD), compared with non-Black patients with SLE.
Now a team of investigators has identified SLE-specific predictors for major cardiovascular complications in Black patients, pointing to potential prevention strategies in this high-risk population.
Among Black patients in a study of 336 patients with incident SLE, discoid rash at the time of SLE diagnosis predicted a fivefold higher risk for stroke, and renal disorder at the time of diagnosis was associated with a twofold higher risk, compared with non-Black patients, but neither of these symptoms predicted elevated risk of IHD.
In contrast, neurologic disorders, including prior psychosis or seizure, were associated with a fourfold higher risk for IHD, and immunologic disorders including anti-DNA, anti-Smith, or antiphospholipid antibodies were associated with a nearly fivefold greater risk for IHD in Black patients, but neither of these comorbidities predicted strokes, reported Shivani Garg, MD, assistant professor of medicine at the University of Wisconsin in Madison.
“Our study was one of the first to highlight racial disparities in CVD subtypes, with a threefold higher stroke risk and 24-fold higher ischemic heart disease risk in Black patients with lupus. Compared to previous studies in Black populations, our study highlights different peak timing of early stroke and ischemic heart disease in our cohort,“ she said at a plenary session during the virtual annual meeting of the American College of Rheumatology.
The study is one of the first to identify specific and unique SLE disease-related predictors of stroke and ischemic heart disease, she said.
Georgia Lupus Registry data
Dr. Garg and colleagues at the University of Wisconsin and Emory University in Atlanta drew on data from the Georgia Lupus Registry, a population-based registry of SLE patients from the Atlanta area. They identified patients diagnosed from 2002 through 2004 who had four or more ACR criteria for SLE, or three or more criteria plus a final diagnosis of SLE made by their board-certified rheumatologists.
The patients were matched to the Georgia Hospital Discharge Database and National Death Index from 2000 through 2013, with stroke- and IHD-related hospitalizations and deaths classified by the first three admission codes or cause-of-death codes.
Patients with transient ischemic attacks were included in the stroke category, and those with myocardial infarction and angina were included in the IHD category.
They identified 336 patients, 87% of whom were female, and 75% of whom were Black. The mean age at SLE diagnosis was 40 years. Among this cohort, there were 38 stroke-related events or deaths and 25 IHD-related events or deaths recorded from the period 2 years before through 14 years after an SLE diagnosis.
Early stroke, late IHD
The investigators first looked at the timing of stroke vs. IHD and found that a disproportionately high percentage of stroke events occurred in the second year after SLE diagnosis, whereas the peak of IHD-related events occurred in the 14th year after diagnosis.
They then performed a race-stratified Cox proportional hazard analysis, and found a threefold higher risk for stroke in Black patients versus non-Black patients (P = .007) and a 24-fold higher risk for IHD (P < .0001).
In multivariate analysis, significant predictors of stroke were Black race with a hazard ratio (HR) of 3.4 (P = .028), discoid rash (HR, 4.6; P = .0028), and renal disorder (HR, 2.4; P = .04). However, stroke was not predicted by age, sex, immunologic disorder, serositis, hematologic disorder, or ACR criteria total greater than four.
Significant predictors of IHD included age 65 and older (HR, 61; P = .0007), Black race (HR, 24; P = .004), neurologic disorder (HR, 4.0; P = .018), and immunologic disorder (HR, 4.7; P = .02). But IHD could not be predicted by oral ulcers, discoid rash, or ACR criteria more than four.
“In future studies, we will examine mechanisms that drive the different timing and predictors of CVD subtypes and disparities. We will also examine the impact of timely prevention in high-risk SLE subsets,” Dr. Garg said.