The present study observed significant differences related to age, BMD of the hip, disease duration, glucocorticoid treatment duration between patients with and without vertebral fractures in the glucocorticoid-induced osteoporosis group. However, no significant inter-subgroup differences were observed related to the BMD of the lumbar spine, as well as the current and cumulative doses of glucocorticoid. The result of multivariate logistic regression analysis demonstrated that the incidence of vertebral fracture was associated with disease duration, disease duration subtracted from age, BMI, and the total hip BMD.
Nonetheless, there is a mismatch between BMD data and fracture data in patients treated with glucocorticoid because of the disparity related to the alteration of bone quality. Previous studies have reported that degenerative disease of the lumbar spine and previous vertebral fracture increased BMD of the lumbar spine in elderly patients (26, 27). Some other studies have reported that the BMD of the femur was associated with the risk factors of osteoporosis, including older age, prolonged disease duration, and low BMI in patients with rheumatological diseases (28, 29). These results were consistent with the results of the present study. Nevertheless, hip BMD could be crucial and efficient in predicting future vertebral fractures in patients with a history of vertebral fracture.
Similar to primary osteoporosis, age, female sex, low BMI, history of falls, previous fractures, duration of menopause, and smoking are associated with fracture risk in patients on glucocorticoid. Nevertheless, a two-fold increase in vertebral fracture risk is noted in patients on glucocorticoid. A large-scale study that compared patients on glucocorticoid and controls determined that the risk of hip fracture was 1.6 fold, and the risk of vertebral fracture was 2.6 fold (5). A previous study involving 551 patients on long-term glucocorticoid treatment reported a 37% prevalence of vertebral fracture, with 48% of patients being more than 70 years old (30). The prevalence of vertebral fracture increases with age and long-term glucocorticoid use. Several observational studies have been conducted regarding the prevalence of vertebral fracture and its relationship with the dose of glucocorticoid treatment. These studies determined that a high-dose glucocorticoid treatment, as well as a high cumulative glucocorticoid dose, were related to vertebral fracture (31, 32). Few studies have reported that the fracture risk was more related to the current daily dose than the cumulative dose(4). The present study demonstrated a significant difference in glucocorticoid treatment duration between patients with and without vertebral fractures. However, no significant differences related to the current and cumulative doses of glucocorticoid between groups were observed. Glucocorticoid treatment duration might be more importantly related to vertebral fractures compared with the dose of glucocorticoid. Notably, patients’ characteristics and osteoporosis treatment were not uniform among studies. Hence, these factors might influence the effects of glucocorticoid dose on vertebral fracture. Therefore, the results of these studies indicating the effects of glucocorticoid dose are debatable.
Nonetheless, our study had several limitations. First, this study was performed as a retrospective and cross-sectional study. We assessed the factors related to vertebral fracture retrospectively. Hence, further large-scale prospective studies are warranted to identify the risk factors of vertebral fracture. Second, the serum bone turnover markers and serum vitamin D levels were not measured in the present study. Third, the treatment agents used for osteoporosis and treatment duration were not uniform among the study patients. Therefore, future studies should consider assessing the risk factors of vertebral fracture in patients with uniform treatment history. Finally, underlying rheumatological diseases were not uniform in the study participants.
In conclusion, the present study indicated that disease duration, BMI, and the total hip BMD were independent risk factors of vertebral fractures in patients with glucocorticoid-induced osteoporosis. Hence, physicians should be aware that patients with longer disease duration, longer glucocorticoid treatment duration, low BMI, and low total hip BMD could be at a high risk of vertebral fracture and may require osteoporosis treatment similar to that provided for primary rheumatological diseases. Patients with rheumatological disease needing glucocorticoid should be treated with anti-resorptive agents at the early phase of glucocorticoid treatment for primary rheumatological disease. In cases with insufficient treatment effects of anti-resorptive agents, physicians should consider the treatment of teriparatide or other new therapeutic agents for osteoporosis.