Administration of Intravenous Zoledronic Acid Every 3 Months vs. Annually in β-thalassemia Patients with Low Bone Mineral Density: a Retrospective Comparison of Efficacy

INTRODUCTION: The benefit of annual administration of zoledronic acid in the management of thalassemia-associated osteoporosis is unknown. AIM: The aims of this study were to evaluate the efficacy of treatment with two different dosing regimens of IV zoledronic acid (annually versus every 3 months) for increasing low bone mineral density (BMD) in patients with osteoporosis associated with β-thalassemia as annually and 3-monthly on bone density in patients. MATERIALS AND METHODS: This retrospective, single-center study analyzed patients’ clinical records and bone density measurements. Those enrolled in the study were 14 to 53 years of age, had documented β-thalassemia, and were treated with IV zoledronic acid on either an annual or every 3 months dosing regimen. Dual-energy X-ray absorptiometry was used to obtain the z-score for BMD in the lumbar spine and femoral neck. RESULTS: Thirty-four patients were enrolled in the study; 15 (44.1%) had been treated annually, and 19 (55.9%) had been treated every month. In patients receiving treatment with the once-yearly dose of zoledronic acid, significant increases were observed in the lumbar spine BMD z-score, from -2.45 ± 0.69 to -1.97 ± 0.82 (P=0.02). When comparing BMD across the two treatment regimens, the mean lumbar spine BMD was 0.82 greater (95% CI 0.31, 1.33, P=0.003) and the mean femoral neck BMD 0.37 greater (95% CI -0.15, 0.87, P=0.1) in the group receiving annual zoledronic acid treatment. CONCLUSIONS: In patients with thalassemia-associated osteopenia, annual treatment with zoledronic acid increases lumbar spine bone density while being more effective, less expensive, and associated with fewer adverse events than dosing every 3 months.