[The effect of long-term low dose prednisone on bone mineral density in patients with systemic lupus erythematosus].

Objective

To investigate the effect of long-term low dose prednisone administration on bone mineral density (BMD) in patients with inactive systemic lupus erythematosus (SLE).

Methods

A total of 118 inactive female SLE patients with long-term administration of low dose prednisone were recruited from the Department of Rheumatology and Immunology at An hui Provincial Hospital.All patients were given low dose prednisone for long-term (≤10 mg/d, more than half a year). According to prednisone doses, subjects were divided into two groups, namely group A (≤7.5 mg/d) and group B (7.5-10 mg/d). In addition, patients were also divided into four groups based on the duration of administration, including groupⅠ≤3 years, Ⅱfrom 4-5 years, Ⅲ 6-10 years and Ⅳ>10 years.Twenty-nine healthy people were recruitedas normal controls.The BMD was measured by dual energy X-ray absorptiometry.The association of BMD with prednisone dose and duration was compared between different groups.

Results

The incidence of osteopenia in all patients with SLE was 42.4%(50/118), and the incidence of osteoporosis was 14.4%(17/118). BMD of all bone sites in both group A and B were significantly lower than that in normal control group (P<0.05). Similarly, the BMD of all bone sites in groupⅠ, Ⅱ, Ⅲ and Ⅳ were significantly decreased (P<0.05). What needed to be stressed was the BMD in group Ⅳ was lower than those in other three groups (P<0.05). Multiple logistic regression analysis showed that the cumulative prednisone dose was the risk factor for osteopenia, while taking calcium and alfacalcidol were protective factors.

Conclusion

Long-term use of low dose prednisone result in the decrease of BMD in patients with inactive SLE.The lumbar spine and femoral neck had more severe osteopenia. Long-term administration of prednisone, even less than 7.5 mg/d, can also cause osteopenia.Calcium and alfacalcidol were protective factors of BMD.