Introduction: Patients with systemic lupus erythematosus (SLE) are at an increased risk of developing low bone mass (LBM) or osteoporosis, either because of the disease itself or due to its treatment. Osteoporosis and osteoporotic fractures significantly contribute to morbidity and mortality. We aimed to determine the associations of bone mineral density (BMD) changes with the duration of SLE, age, gender, and glucocorticoid treatment in SLE patients treated at our Department.
Patients and methods: BMD measurements of the lumbar spine and total hip were performed by dual-energy X-ray absorptiometry (DXA). Osteoporosis and LBM were determined according to the 1994 World Health Organization definition. In the statistical analysis, the independent Mann-Whitney U test and Tukey post-hoc testing were used.
Results: The study included 48 SLE patients (44 female and 4 male), with a mean age of 45.8 years and an average SLE duration of 9.8 years. Osteoporosis was diagnosed in 21%, and LBM in 15% of the patients. The mean ages of the subgroups with normal BMD, LBM, and osteoporosis were 41.1, 47.6, and 59.0 years, respectively. Variant analysis showed a statistically significant correlation between age and BMD (p < 0.05). The duration of SLE was significantly shorter in patients with normal BMD (7.3 years), compared to patients with LBM (16.1 years) and osteoporosis (12.9 years) (p < 0.05). Nearly all patients (47 of 48) were on long-term treatment with glucocorticoids. One third (33.3 %) of patients did not take vitamin D3, and 56.3 % did not take calcium supplements.
Conclusion: The etiopathogenesis of decreased BMD in SLE patients is multifactorial and includes both traditional and SLE-related risk factors. In our group of SLE patients age and glucocorticoid treatment were the major risk factors for LBM. Timely prevention and treatment of LBM and osteoporosis in SLE patients, according to current knowledge, are essential for reducing morbidity and mortality.