IMPORTANCE Postmenopausal status coincides with increased risks for chronic conditions such as heart disease, osteoporosis, cognitive impairment, or some types of cancers. Previously, hormone therapy was used for the primary prevention of these chronic conditions.
OBJECTIVE To update evidence for the US Preventive Services Task Force on the benefits and harms of hormone therapy in reducing risks for chronic conditions.
DATA SOURCES MEDLINE, Cochrane Library, EMBASE, and trial registries from June 1, 2011, through August 1, 2016. Surveillance for new evidence in targeted publications was conducted through July 1, 2017.
STUDY SELECTION English-language randomized clinical trials reporting health outcomes.
DATA EXTRACTION AND SYNTHESIS Dual review of abstracts, full-text articles, and study quality; meta-analyses when at least 3 similar studies were available.
MAIN OUTCOMES AND MEASURES Beneficial or harmful changes in risks for various chronic conditions.
RESULTS Eighteen trials (n = 40058; range, 142-16 608; mean age, 53-79 years) were included. Women using estrogen-only therapy compared with placebo had significantly lower risks, per 10000 person-years, for diabetes (-19 cases [95% CI, -34 to -3]) and fractures (-53 cases [95% CI, -69 to -39]). Risks were statistically significantly increased, per 10000 person-years, for gallbladder disease (30 more cases [95% CI, 16 to 48]), stroke (11 more cases [95% CI, 2 to 23]), venous thromboembolism (11 more cases [95% CI, 3 to 22]), and urinary incontinence (1261 more cases [95% CI, 880 to 1689]). Women using estrogen plus progestin compared with placebo experienced significantly lower risks, per 10000 person-years, for colorectal cancer (-6 cases [95% CI, -9 to -1]), diabetes (-14 cases [95% CI, -24 to -3), and fractures (-44 cases [95% CI, -71 to -13). Risks, per 10000 person-years, were significantly increased for invasive breast cancer (9 more cases [95% CI, 1 to 19]), probable dementia (22 more cases [95% CI, 4 to 53]), gallbladder disease (21 more cases [95% CI, 10 to 34]), stroke (9 more cases [95% CI, 2 to 19]), urinary incontinence (876 more cases [95% CI, 606 to 1168]), and venous thromboembolism (21 more cases [95% CI, 12 to 33]).
CONCLUSIONS AND RELEVANCE Hormone therapy for the primary prevention of chronic conditions in menopausal women is associated with some beneficial effects but also with a substantial increase of risks for harms. The available evidence regarding benefits and harms of early initiation of hormone therapy is inconclusive.