Negative correlation between fetuin-A and indices of vascular disease in systemic lupus erythematosus patients with and without lupus nephritis.

INTRODUCTION Fetuin-A, a systemic calcification inhibitor, has been negatively related to vascular calcification (VC) and cardiovascular mortality. In this study we investigated the association between fetuin-A levels and atherosclerotic vascular complications in systemic lupus erythematosus (SLE) patients with and without lupus nephritis (LN). METHODS We recruited 20 SLE patients without LN, 20 SLE patients with LN and 20 healthy controls. We determined serum creatinine, lipid profile, high sensitivity C-reactive protein (hsCRP), calcium, phosphate and fetuin-A levels, and calculated the calcification risk index (CRI) and SLE disease activity index (SLEDAI) for all subjects. Vascular disease burden was assessed by quantification of carotid artery intima-media-thickness (IMT) and the ankle-brachial index (ABI). RESULTS Fetuin-A levels were significantly lower in LN patients (0.47 ± 0.1 g/L) compared to SLE patients without LN (0.54 ± 0.1 g/L) and both were significantly lower than controls (0.78 ± 0.2 g/L). CRI was significantly higher in LN patients (89.1 ± 12.1 mg/L) compared to SLE patients without LN (67.2 ± 9.3 mg/L) and both were significantly higher than controls (34.2 ± 6.2 mg/L). Peripheral arterial disease (ABI > 0.9) was significantly more common in LN patients (55%) compared to SLE patients without LN (30%) as well as controls (0%). Fetuin-A levels showed significant negative correlations with serum creatinine, hsCRP, CRI, IMT and ABI in SLE patients with and without LN. CONCLUSION Fetuin-A levels were decreased in SLE patients with and without LN and negatively correlated with vascular complications. This suggests a potentially important role for fetuin-A deficiency as marker of vascular disease in SLE patients with and without LN.