Notable difference between the development of vertebral fracture and osteonecrosis of the femoral head in patients treated with high-dose glucocorticoids for systemic rheumatic diseases

Objective: Vertebral fracture (VF) and osteonecrosis of the femoral head (OFH) are serious concerns in patients with rheumatic diseases treated with high-dose glucocorticoids (GCs). We comparatively examined the risk factors of VF and OFH in patients who had recently received high-dose GC therapy. Patients and Methods: Patients with rheumatic diseases receiving GCs (≥0.5 mg/kg/day for prednisolone equivalent) within the past 2 months were enrolled in this study, and treated with 200 mg/day of etidronate cyclically. The bone mineral density (BMD) of the lumbar spine (L2-4) was examined by QDR2000. OFH was evaluated by magnetic resonance imaging (MRI). [ClinicalTrials.gov identifier: NCT00679978]. Results: Forty-four patients completed the 2-year study including annual X-rays and the BMD analysis. MRI evaluation at entry and 2 years was performed in 41 patients. The BMD values with anteroposterior (AP) and lateral views decreased by 6.4% and 9.7%, respectively, in the first year, but were stable in the second year. Eleven patients developed VF and 9 patients developed OFH. The risk factors for VF included previous VF and a low BMD value (T score<-1.5) of AP view at baseline with an odds ratio (OR) of 14.9 (95% CI 2.9-76.4), while the risk factor for OFH was a recent maximum GC dosage (>1.2 mg/kg/day versus≤; OR=7.7, 95%CI 1.3-45.5) and a decrease in BMD value of lateral view (>15% versus≤ OR=6.7, 95% CI 1.2-36.1) in the first year. Conclusion: The development of VF relies on the predisposing factors, while that of OFH depends on the response to high-dose GC therapy.