Clinical analysis of bone mineral density in patients with newly diagnosed untreated systemic lupus erythematous / 中华风湿病学杂志

ABSTRACT

Objective:The study was aimed to investigate the bone mineral density (BMD) status of newly diagnosed systemic lupus erythematous (SLE) patients.Methods:Newly diagnosed SLE patients and healthy controls in Peking University Third Hospital from 2014 to 2018 were enrolled into this cross-sectional study. Medical records including systemic lupus erythematosus disease activity index (SLEDAI)-2000 and BMD of the lumbar vertebrae and hips measured by dual-energy X-ray absorptiometry were collected. Patients were divided into normal and low BMD groups. Parameters were compared by Student- t test, Mann-Whitney U test and χ 2 test. Results:Eighty-nine patients and 20 healthy controls were included. Approximately 52.8% of the SLE patients had low BMD. Compared to the healthy control group, the BMD of lumbar spine and hip was obviously lower than in the newly diagnosed SLE group[(0.97±0.14) g/cm 2, (1.08±0.10) g/cm 2, t=3.548, P<0.01; (0.88±0.15) g/cm 2, (1.00±0.08) g/cm 2, t=3.878, P<0.01]. The BMD of lumbar spine and hip in the low BMD group was lower than that in the normal BMD group [(0.88±0.10) g/cm 2, (0.80±0.11) g/cm 2; (1.07±0.11) g/cm 2, (0.97±0.13) g/cm 2, respectively]. Compared with the normal BMD group, the body mass index (BMI) was significantly lower [(19.2±2.0) kg/m 2, (23.2±3.6) kg/m 2 respectively, t=3.678, P<0.01], the disease duration was longer [(45.7±7.7) weeks, (16.0±19.5) weeks, respectively, t=-3.306, P<0.01). Patients with low BMD tended to have lower 25-hydroxy-vitamin-D(25-OH-VD 3) level and higher bone metabolism marker levels (Degradation products of collagen B) [(9±5) nmol/L vs (12±7) nmol/L, t=1.385, P>0.05; 0.62(0.21, 1.61) ng/ml vs 0.43(0.19, 0.88) ng/ml, Z=0.624, P>0.05], although their differences didn't reach the statistical significant difference. Conclusion:Newly diagnosed SLE patients' BMD is lower than the healthy people. About 52.8% newly diagnosed untreated SLE patients have low BMD. Lower BMI and longer disease duration are their clinical characteristics. High bone metabolism marker levels, low 25-hydroxy-vitamin-D level might have clinical significance, although the current findings do not find statistically significant difference. Large sample size is required for subsequent research analysis.