Objective: The aim of this study was to measure serum oxidized low-density lipoprotein (Ox-LDL) levels in patients with rheumatoid arthritis (RA) or systemic lupus erythematosus (SLE) and to identify any association with clinical variables.
Methods: We studied 126 female patients (27 with active RA, 27 with inactive RA, 72 with SLE). One hundred fifteen age-matched healthy women (76 for RA, 39 for SLE) with no clinical or laboratory evidence of disease served as normal controls. Serum Ox-LDL levels were measured with a commercial enzyme-linked immunosorbent assay kit (Mercodia, Sweden).
Results: The serum Ox-LDL levels were significantly higher in patients with active RA (P<0.05) or SLE (P<0.01) than age-matched controls and significantly higher in patients with active RA than with inactive RA (P<0.01). The levels of serum total cholesterol and LDL were significantly lower in patients with RA than in age-matched controls (P<0.01). There was no correlation among serum Ox-LDL levels and inflammatory markers (erythrocyte sedimentation rate, C-reactive protein) or rheumatoid factors in patients with RA.
Conclusions: Compared with healthy women, those with SLE or active RA had increased serum Ox-LDL levels, which may contribute to the increased risk of cardiovascular disease in this patient group.