Receiver operating characteristic (ROC) curves for association between total body bone mineral density (BMD) (A-B) the middle and upper tertiles of total body BMD, ≥1.067 mg/cm
(C-D) and the upper mean (>0.659 mm) carotid intima-media thickness (cIMT) (A, C) and bilateral carotid plaque (B, D) in patients with systemic lupus erythematosus (SLE). The curves are based on multivariate models with traditional risk factors alone (dashed lines) or together with (solid lines) a low level of complement C4 (<0.13 g/l). For total body BMD in association with higher cIMT (A) areas under the ROC curves are 0.840 (95% CI 0.768, 0.912, P <0.001) and 0.858 (0.789, 0.927, p = <0.001) in corresponding models; and in association with bilateral carotid plaque (B) areas are 0.869 (0.797, 0.940, P <0.001) and 0.886 (0.813, 0.958, P <0.001), respectively. For association between the middle and upper tertiles of total body BMD and upper mean cIMT (C), areas under the ROC curves are 0.850 (0.777, 0.923, P <0.001) in analyses incorporating traditional risk factors, and 0.863 (0.786, 0.941, P <0.001) in models that also included low C4; respective areas for association with bilateral carotid plaque (D) are 0.869 (0.792, 0.946, P <0.001) and 0.911 (0.848, 0.974, P <0.001).