Predictors of skeletal-related events among cancer patients with bone metastases treated with zoledronic acid: a secondary analysis of a randomized study

Background: The purpose of the current study is to assess the predictors of skeletal-related events (SREs) among advanced cancer patients with bone metastases treated with zoledronic acid within a randomized study. Research design and methods: This is a secondary analysis of patient-level data of advanced cancer patients with bone metastases who were treated with monthly zoledronic acid in the NCT00330759 clinical trial. Results: A total of 702 patients were included in the current analysis. In univariate logistic regression analysis, higher body mass index (P = 0.034) and lytic nature of bone metastasis (P = 0.008) were found to be predictive of a higher probability of SREs. When the two factors were included in a multivariate logistic regression model, both of them were predictive of the later development of SREs (P value for higher body mass index = 0.015; P value for lytic bone lesions = 0.005). Conclusion: Among advanced cancer patients with bone metastases, lytic nature of metastases, as well as higher body mass index, are associated with a higher probability of SREs.