Background: Long-term post-menopausal hormone therapy (pHT) was often regarded as first-line therapy to prevent fractures in post-menopausal women, a recommendation under scrutiny given the benefit-risk profile of the Women's Health Initiative results of the estrogen-progestin combination. Apart from controlled clinical studies providing data with fractures as an end point, measures of lumbar and hip bone mineral density (BMD) may be used to assess bone-related effects of pHT. The objective of this study was to conduct a systematic review of 2-year trials, published between 1990 and December 2002, and assessing changes in BMD by any estrogen including ethinyl estradiol, any estrogen plus any progestin, or tibolone.
Methods: We searched MEDLINE, EMBASE and systematic reviews. Thirty-nine randomized, prospective, controlled 2-year trials were analysed in pre-specified groups according to the profile of the compounds.
Results: Virtually all pHT regimens at least maintain BMD at the lumbar spine and the hip compared with baseline; there is no apparent difference between the various estrogenic compounds. Tibolone, a synthetic progestin, appears to be as effective as any estrogen. Most trials were conducted in early post-menopausal women, fewer in women with hysterectomy and/or bilateral oophorectomy.
Conclusions: The size of impact on BMD does not appear to differ between tibolone and any estrogen compound studied.