[Bone mineral density and disease activity in untreated systemic lupus erythematosus patients]

To determine the effects of disease activity and other risk factors on bone mineral density (BMD) in untreated systemic lupus erythematosus (SLE).

Lumbar and hip BMD were determined by dual energy X-ray absorptiometry (DXA) in 50 healthy controls and 120 premenopausal SLE females from Department of Rheumatology & Immunology, Third Hospital of Medical College of Jilin University during the period of 2010 - 2012. The SLE patients were divided into 2 groups, i.e. untreated and treated with glucocorticoid and immunosuppressives. Simple and multiple linear regression analyses were performed to determine the associations between BMD and disease-related variables. To completely eliminate the influences of glucocorticoid treatment on the results, the untreated SLE patients were chosen to investigate the risk factors with regression analysis.

In femoral neck, greater trochanter and total hip, both the treated and untreated SLE patients had significantly lower BMD than the healthy controls (P < 0.01). In greater trochanter, the treated SLE group had significantly lower BMD than the untreated group. The BMD of left and right femoral neck of the former were botj -0.06 while that of the later -0.11 and -0.12 respectively (P < 0.05). Regression analysis showed that long disease duration and high (SLE disease activity index) SLEDAI were the risk factors of low BMD (P < 0.05), especially high SLEDAI.

SLE itself may result in low BMD, especially in patients with high SLEDAI. Hip joints are predominantly affected. Long disease duration is also closely associated with low BMD in SLE.