We studied a total of 21 trials involving 28,425 patients treated with placebo, which were identified through MEDLINE, EMBASE, and Cochrane Central Register of Controlled Trials.
A univariate meta-regression showed a significant correlation between the proportion of subjects experiencing new vertebral fracture and the proportion of Caucasian subjects (coefficient = 0.223, [Formula: see text]), and the proportion of subjects with prevalent vertebral fracture (0.161, [Formula: see text]). Baseline lumbar spine BMD did not show significant correlations. As a result of multivariate meta-regression analysis with the factors with [Formula: see text] by the univariate meta-regression, the proportion of subjects with prevalent vertebral fracture was identified as an influencing factor (0.139, [Formula: see text]).
The multivariate meta-regression showed that prevalent vertebral fracture was the most important factor to predict subsequent vertebral fracture. In addition, considering the results of the univariate meta-regression analysis, we suggest that the ethnic/regional difference should be considered as one of the important factors that influence the incidence of new vertebral fracture, a primary endpoint of osteoporosis study, when the Caucasian reference range is used in clinical trials.