Effects of low-dose hormone therapy on menopausal symptoms, bone mineral density, endometrium, and the cardiovascular system: a review of randomized clinical trials

Objectives First, to determine the extent of the effects of low-dose hormone therapy (HT) on menopausal symptoms, bone mineral density, endometrium, and the cardiovascular system, and, second, to determine the adverse effects of low-dose HT. Methods A literature review of electronic databases was conducted to identify all prospective, randomized trials comparing the effects of low-dose HT with placebo or standard-dose therapy, using key words such as: hormone replacement therapy (HRT), low-dose HRT/conjugated equine estrogens (CEE)/estradiol, lower-dose HRT/CEE/estradiol, ultra-low-dose HRT/CEE/estradiol, menopause, cardiovascular risk, bone metabolism. Results Low-dose HT has been shown to improve menopausal and vulvovaginal atrophic symptoms, compared to placebo, and is less likely to give rise to unacceptable side-effects, including irregular bleeding and/or breast tenderness. When compared to standard-dose HT, the low-dose HT has comparable effects on a range of menopausal symptoms and on bone density and has similar beneficial effects on surrogate end-points of coronary heart disease. Conclusions A change to low-dose HT has been advocated following adverse findings in recent trials of standard-dose HT. Although a literature review has shown low-dose HT to alleviate menopausal symptoms and maintain or improve bone density with fewer side-effects than standard-dose therapy, further research is required to determine what effect the lower-dose therapy will have on fracture, cardiovascular and breast disease.