Assessment of Etidronic Acid plus Alfacalcidol for the Treatment of Osteopenia in Steroid-Dependent Asthmatics

Objective Osteoporosis is generally known to be one of the most serious adverse effects of long-term corticosteroid administration. Recently it was discovered that corticosteroid-induced osteoporosis occurs not only in trabecular bone but also in cortical bone, leading to a reduction in cortical bone strength. To ameliorate corticosteroid-induced bone injury, we administered etidronic acid plus alfacalcidol to five steroid-dependent asthmatics for 4 years and monitored therapeutic responses in trabecular bone and cortical bone using peripheral quantitative computed tomography (pQCT). Patients and interventions The five steroid-dependent asthmatic patients included two males and three females, with a mean age 68.2 years, taking a mean daily dose of oral prednisolone of 7 mg/day. Etidronic acid 200 mg/day was administered for 14 consecutive days every 4 months for 4 years, while alfacalcidol 0.5μg was administered daily for 4 years. Main outcome measures and results Every 4 months, the number of vertebral fractures was assessed by lateral vertebral radiographs, and the total radial bone mineral density (BMD), trabecular BMD, cortical BMD, Relative Cortical Volume (RCV) and Strength Strain Index (SSI) were assessed by pQCT (Stratec XCT-960). At follow-up, no new fractures had occurred, the trabecular BMD was found to be slightly increased (from 117.2 mg/cm 3 at baseline to 121.6 mg/cm 3 after 48 months), and no significant decreases were observed in the total BMD, cortical BMD, RCV or SSI. Conclusion Based on these findings, etidronic acid plus alfacalcidol seems to be effective in preventing steroid-induced bone injury, not only in terms of trabecular and cortical BMD, but also in terms of cortical bone volume and strength, which may lead to a decrease in non-vertebral fractures. However, further investigation is required with a larger sample size and a longer administration period to confirm these findings.