Hormone replacement therapy and prevention of vertebral fractures: a meta-analysis of randomised trials

We searched the main electronic databases until the end of August 2001. We sought all randomised controlled trials (RCTs) of HRT where women had been randomised to at least 12 months of HRT or to no HRT.We found 13 RCTs. Overall there was a 33% reduction in vertebral factures (95% confidence interval (CI) 45% to 98%).This review and meta-analysis showed a significant reduction in vertebral fractures associated with HRT use.Hormone replacement therapy (HRT) is often considered to reduce vertebral fractures by about 60% [1]. This view is based upon the results of one trial, which counted the number of fractures rather than the number of women with fractures. If an analysis is undertaken looking at the number of women with an incident vertebral fracture the reduction is less and is not statistically significant [2]. We have recently reported in a systematic review of 22 randomised-controlled trials that hormone replacement therapy (HRT) reduces non-vertebral fractures by about 30% [3]. To see if there were a similar effect on vertebral fractures we have extended our review to include such fractures.Our search strategy has been previously reported; [3] however, in brief, we searched all the main electronic databases for any RCT of HRT and contacted investigators for unpublished data. There were no language restrictions. To be included in the review trials had to be longer than 12 months and include a comparator group who were either taking an inactive placebo, calcium with or without vitamin D, or using no treatment. Up until the end of August 2001, after excluding duplicate reports, we identified 72 potentially relevant trials.We identified 13 eligible studies. Nine of which came from our original review of 22 trials [4-12]. The four additional trials, not previously included, were identified as follows. Two trials were excluded from our previous review as they only reported vertebral fractures [1,13] and are now included and two further studies were identified in a re