Quantitative ultrasound of bone and clodronate effects in thalassemia-induced osteoporosis

Abstract

Osteoporosis in beta-thalassemia major has emerged as a topic of interest since optimized transfusion regimens have increased life expectancy and quality in these patients. Although the pathogenesis of thalassemic osteopathy is multifactorial, the evidence of an increased resorption phase suggests that the use of antiresorptive drugs such as bisphosphonates can be considered a valuable therapeutic strategy to reduce bone turnover and the risk of fragility fractures. We compared the effects of long-term cyclical clodronate therapy (300 mg intravenous infusion every 3 weeks for 2 years) and of an active placebo (calcium 1 vitamin D) on bone mass and bone turnover in 30 male patients with beta-thalassemia major. We also tested the possibility of using quantitative ultrasound (QUS) for assessing bone involvement in thalassemic osteopenia and in monitoring the response to antiresorptive therapy. Broadband ultrasound attenuation (BUA) was significantly reduced in patients with beta-thalassemia major as compared to healthy controls. In calcium and vitamin D-treated patients, a significant decline in spine, femoral, and total body areal bone density was observed. In the patients given intravenous clodronate we measured a substantial stability of bone mass, which was not significantly changed at the end of the study. The urinary excretion of deoxypyridinoline (a marker of bone resorption) showed a progressive significant decline throughout the study period in clodronate-treated patients. No significant change was observed in BUA values in both groups of patients. These results indicate that intermittent intravenous clodronate administration was not able to increase areal bone density in our thalassemic patients. Moreover, this is the first study to have assessed the usefulness of broadband ultrasound measurements in beta-thalassemia major.