Analysis of factors associated with bone mineral density in patients with lupus nephritis

Objective There is a growing incidence of lower bone mineral density （BMD） in patients with lupus nephritis （LN）. The goal of this study was to explore the possible related factors of BMD in LN patients. Methods Between May 2016 and June 2022, BMD was measured by dual X-ray absorptiometry （DXA） at lumbar spines of L1～L4, total hip and femoral neck in 91 female patients. Results The mean age was 47.2 years. And 60.4% of them were postmenopausal and 97.8% received glucocorticoids. There were low BMD （69.2%）, osteopenia （63.7%） and osteoporosis （22.0%）. For preventing osteoporosis, the medications included calcium （87.9%）, α calcitriol （35.2%） and bisphosphonates （53.8%）. Multiple linear regression analysis revealed that body weight was an independent correlation factor for BMD of lumbar spine （L1～L4） （β = 0.008, P＜0.001）, total hip （β = 0.016, P＜0.001） and femoral neck （β = 0.016, P＜0.001）. And menopausal duration was an independent correlation factor for BMD of lumbar spine （L1～L4） （β = −0.011, P = 0.038） and total hip （β = −0.01, P = 0.017）. Conclusions LN patients have a high prevalence of lower BMD. Low body weight and menopause duration may be the possible associated factors of BMD.