Background SLE is a strong risk factor for premature CVD and mortality. We investigated which factors could explain poor prognosis in SLE compared with controls.

Methods Patients with SLE and age- and sex-matched controls were recruited for this prospective study. Carotid ultrasound was performed at inclusion. The outcome was incident CV event and death. Event-free survival rates were compared using Kaplan-Meier curves. Relative hazard ratios (HRs, 95%CI) were used to estimate the risk of the outcome.

Results The patients, n=99, 87% females, were mean (SD) 47 (13) years old, had disease duration of 12 (9) years. The controls, n=109, 91% females, were mean 49 (12) years old. Baseline carotid intima-media thickness (cIMT) did not differ between the groups. During 9.6 (1.5) years, 12 patients and 4 controls were documented with the outcome, p=0.022. Compared with the controls, the risk of the outcome in the patients was 3–4-fold increased at the same level of traditional CV risk factors and carotid measures. SLE-patients with poor outcomes had higher cIMT, SLICC, APS diagnosis and used prednisolone longer time than those without. Higher SLICC and APS diagnosis were associated with increased risk of the poor outcome, respective HRs 1,66 (1.20–2.28) and 9.08 (2.71–30.5), as well as with cIMT, HR 1.006 (1.002–1.01), independent of age and sex. The combination of SLICC and APS with cIMT significantly improved outcome prediction, p<0.001.

Conclusions Patients with SLE compared with controls at the same level of CV risk factors and cIMT had increased long-term risk of clinical events. Applying accumulated disease-damage, APS and cIMT may improve risk stratification in SLE.