Ranking antireabsorptive agents to prevent vertebral fractures in postmenopausal osteoporosis by mixed treatment comparison meta-analysis

INTRODUCTION: Bisphosphonates are considered as a first-line therapy for the prevention and treatment of osteoporosis, showing in double-blind, randomized, controlled trials a significant reduction of incidence of new vertebral fractures compared to placebo. Recently also, Denosumab has been shown to reduce the appearance of new vertebral fractures by blocking RANK. There are not head to head comparative studies between the above mentioned drugs. Mixed treatment comparison, an extension of traditional meta-analysis, is able to compare simultaneously several drugs across a range producing a synthetic evidence of efficacy and a range of probability as to the best treatment. OBJECTIVES: The aim of this study is to simultaneously compare alendronate, risedronate, ibandronate, zolendronate and denosumab in the prevention of OP vertebral fractures in a Bayesian meta-analysis for assessing indirect comparisons. MATERIALS AND METHODS: A search for randomized controlled trials involving alendronate, risedronate, ibandronate, zolendronate and denosumab was conducted using several databases. Randomized controlled trials (RCTs) with a double blind treatment period of at least 3 years were included. Men and Glucorticoid Induced osteoporosis, RCTs having as primary or secondary endpoints continuous values as body mineral density (BMD) and studies comparing different dosing regimens of the same agent, which are not used in clinical practice, were excluded. Only fully published reports were considered. RESULTS: A total of 9 RCTs were identified providing data on 31,393 participants. Zolendronate had the highest probability (52%) of being the most effective treatment towards placebo, followed by denosumab (46% probability), ibandronate and then alendronate and risedronate against placebo. CONCLUSIONS: Although the mixed treatment comparisons among alendronate, risedronate, ibandronate, zolendronate and denosumab did not show a statistically significant difference, this analysis suggests that zolendronate, compared to placebo, is expected to provide the highest rate of reduction in vertebral fractures affecting osteoporosis affected patients.