Bone Abstracts

Introduction: To analyze clinical assessment and efficacy of once-yearly i.v. zoledronic acid for osteoporosis.

Materials and methods: The subjects were 322 osteoporotic patients who received more than single infusion of zoledronic acid in our hospital from October 2008 to March 2011. On clinical assessment, the adherence was evaluated by measuring the rate of reinfusion. Adverse events were recorded for safety assessment. For efficacy assessment, the bone mineral density (BMD) and bone turnover marker were measured before and after infusion.

Results: Excluding the patients lost to follow-up after 1 year, 107 patients (47.6%) received the second infusion, continuously. For patients with second infusion, 41 patients (51.3%) persistently received the third infusion, except the patients lost to follow-up. The economic strain was the most common reason for non-adherence which accounted for 43.4%, and the incognition or the indifference was the second most common reason for non-adherence making up 30.8%. The adverse events were reported for 122 patients (38.2%), but the serious adverse events were not reported BMD at baseline was mean −3.24±0.63 by T-score. Mean BMD was measured at −2.98±0.65 and −2.82±0.59 in 1 and 2 years follow-up, respectively, and significantly increased (Pvalue <0.001). C-telopeptide at baseline was mean −0.34±0.34. Mean C-telopeptide was measured at −0.20±0.11 and −0.23±0.11 in 1 and 2 years follow-up, respectively, and significantly decreased (Pvalue=0.003).

Conclusion: In this study, the infusion of once-yearly i.v. zoledronic acid for osteoporotic patients decreased bone resorption and improved bone mineral density. Serious adverse events were not reported. The adherence was higher than most published studies of adherence to oral bisphosphonates, but lower than optimal. Because incognition or indifference was major cause of non-adherence, the physicians should explain the efficacy and adverse effect of this agent.