Randomized trial comparing efficacies of zoledronate and alendronate for improving bone mineral density and inhibiting bone remodelling in women with post-menopausal osteoporosis

WHAT IS KNOWN AND OBJECTIVE: Bisphosphonates are the first-line medications for treating osteoporosis. The aim of our prospective study was to compare the efficacy of zoledronate with that of alendronate in women with post-menopausal osteoporosis based on the evaluations of bone mineral density (BMD) and serum levels of biochemical markers of bone remodelling. METHODS: Chinese women with post-menopausal osteoporosis were randomly assigned to the zoledronate (n = 52) or alendronate (n = 53) group, and were treated with 5 mg zoledronate intravenously once per year and 70 mg alendronate orally once per week, respectively. During a 3-year follow-up period, the lumbar spine, femoral neck and total hip were examined using dual-energy x-ray absorptiometry every 12 months to assess BMD, and the serum levels of amino-terminal propeptide of type I procollagen (P1NP) and carboxy-terminal cross-linked telopeptides of type 1 collagen (CTX) were measured to evaluate bone formation and resorption, respectively. RESULTS AND DISCUSSION: Greater increases in BMD occurred in the zoledronate group over the 3-year follow-up period, with increases in BMD of 41·3%, 13·5% and 20·0% at the lumbar spine, femoral neck and total hip, respectively, compared with 16·9%, 5·88% and 8·93% in the alendronate group, respectively (P < 0·05 for all). At the 3-year follow-up, P1NP and β-CTX levels were reduced by 42·1% and 50·5% in the zoledronate group, respectively, whereas the levels of each were reduced by 19·5% and 19·4% in the alendronate group, respectively (P < 0·05 for all). WHAT IS NEW AND CONCLUSIONS: Once yearly zoledronate administered intravenously was more efficacious for improving BMD and reducing the serum levels of P1NP and β-CTX in Chinese women with post-menopausal osteoporosis than alendronate administered orally once per week. The incidence of adverse events after the second and third zoledronate treatments was substantially lower than that in the alendronate group, suggesting a substantially lower risk of adverse events with long-term use of zoledronate in Chinese women, compared with that of alendronate use.