Objective Systemic Lupus Erythematosus (SLE) patients without prior cardiovascular events present an increased prevalence of atherosclerotic carotid plaques, coronary artery calcifications (CAC), and signs of peripheral artery disease compared to matched healthy population controls (HC). Thus, we investigated whether vascular calcifications in SLE are distributed differently from those of HC and whether distributional differences are associated with SLE disease characteristics incl. non-vascular calcifications. We hypothesized that the amount and distribution of atherosclerotic changes in distinct areas of the vascular bed in SLE patients differ from that of age- and sex-matched HC. Such variation may be in part attributable to specific phenotypes of SLE and associated with calcifications outside the aorta and coronary arteries.

Methods For this cross-sectional matched case-control study, 113 SLE patients from the PLUSheart (Prospective Lupus Study on Cardiovascular Risk Factors) cohort established at Copenhagen University Hospital, Denmark, in 2012–13 were matched 1:2 by age and sex to HC from the Copenhagen General Population Study (CGPS) cohort. Subjects were split into age-matched subgroups below and above 50 years. CAC was evaluated using a non-contrast, prospectively ECG-gated cardiac protocol on a 320-multidetector CT scanner. Phases were reconstructed in 3.0 mm slice thickness with a 3.0 mm increment. The total amount of CAC was measured in volume (mm3).

Results Among 336 subjects aged 35–75 years included in this study, SLE patients more often had CAC (48%) compared to HC (29%). This was most pronounced for subjects aged less than 50 years (OR: 9.76 [95%CI: 3.1–31], table 1). The relative anatomical distribution of CAC did not differ between SLE and HC. SLE patients also had more frequent calcifications outside the coronary artery bed i.e., aortic and mitral valves, aortic arch, and calcifications in organs (OR: 2.83–9.72), which for the latter was also most pronounced in subjects aged less than 50 years (table 2). As for CAC, multiplicative interaction between having SLE and organ calcifications was observed (OR: 5.48 [95%CI: 1.2–25]).

Conclusion The findings suggest that in a subset of SLE patients, CAC differs from what is seen in the general population, quantitatively as well as qualitatively.

Acknowledgments The Danish Rheumatism Association.