Our ultimate goal is to identify and target modifiable risk factors that will reduce major cardiovascular events in African-American lupus patients. As a first step toward achieving this goal, this study was designed to explore risk factor models of preclinical atherosclerosis in a predominantly African-American group of SLE patients using variables historically associated with endothelial function in non-lupus populations.
51 subjects with SLE but without a history of clinical cardiovascular events were enrolled. At entry, a Framingham risk factor history and medication list were recorded. Sera and plasma samples were analyzed for lipids, lupus activity markers, and total 25-hydroxyvitamin D (25(OH)D) levels. Carotid ultrasound measurements were performed to determine total plaque area (TPA) in both carotids. Cases had TPA values above age-matched controls from a vascular prevention clinic population. Logistic regression and machine learning analyses were performed to create predictive models.
25(OH)D levels were significantly lower and SLE disease duration was significantly higher in cases. 25(OH)D levels inversely correlated with age-adjusted TPA. ACE-inhibitor non-use associated with case status. Logistic regression models containing ACE-inhibitor use, 25(OH)D levels, and LDL levels had a diagnostic accuracy of 84% for predicting accelerated atherosclerosis. Similar results were obtained with machine learning models, but hydroxychloroquine use associated with controls in these models.
This is the first study to demonstrate an association between atherosclerotic burden and 25(OH)D insufficiency or ACE-inhibitor non-use in lupus patients. These findings provide strong rationale for the study of ACE-inhibitors and vitamin D replenishment as preventive therapies in this high-risk population.