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The menopause and HRT. Hormone replacement therapy, cardiovascular and cerebrovascular disease
1Monash University Department of Medicine, Vascular Medicine and Sciences Unit, Dandenong Hospital, David Street, Dandenong, Victoria 3175, Australia. h.teede@southernhealth.org.au
Insights
Hormone replacement therapy (HRT) research shows past enthusiasm for cardiovascular protection in women was misplaced. Recent trials indicate HRT may slightly increase vascular risks, necessitating caution.
Area of Science:
- Cardiovascular Science
- Endocrinology
- Women's Health
Background:
- Observational studies suggested hormone replacement therapy (HRT) protected post-menopausal women against coronary heart disease (CHD).
- Mechanistic studies supported beneficial vascular effects of HRT.
- Translating research findings into clinical practice for HRT has proven challenging.
Purpose of the Study:
- To evaluate the vascular effects of hormone replacement therapy (HRT) in post-menopausal women.
- To contrast findings from observational studies with recent controlled trial data.
- To inform clinical practice regarding HRT use for vascular disease prevention.
Main Methods:
- Review of historical observational trials on HRT and cardiovascular outcomes.
- Analysis of recent controlled trials investigating combined oral HRT.
- Comparison of HRT effects against placebo for cardiovascular and cerebrovascular events.
Main Results:
- Recent controlled trials revealed a small increased risk of cardiovascular and cerebrovascular events with a specific combined oral HRT compared to placebo.
- These risks were associated with increased incidence of venous thrombosis and breast cancer.
- Absolute risk increases were noted to be small.
Conclusions:
- Current evidence suggests all forms of HRT should be presumed to carry a small vascular risk until proven otherwise.
- The lack of HRT effectiveness in vascular disease prevention should not diminish focus on established preventive strategies.
- Lifestyle measures remain a key component of vascular disease prevention in post-menopausal women.
Abstract:
Historically, research into vascular effects of hormone replacement therapy (HRT) poignantly highlights the difficulties in extrapolating from medical research into clinical practice. Original observational trials encouraged great enthusiasm that HRT was protective against coronary heart disease (CHD) in post-menopausal women. This was supported by a plethora of beneficial mechanistic effects of HRT on the vascular system. In contrast, recent controlled trials have shown that a specific combined oral HRT actually causes a small increased risk of cardiovascular and cerebrovascular events, compared to placebo. The absolute risks were small, yet were accompanied by increased venous thrombosis and breast cancer. Although many controversies still remain regarding the vascular effects of specific types of HRT, currently, in my opinion, all HRT should be considered as causing a small increased risk of vascular events, until proven otherwise. However, the apparent lack of HRT effectiveness in the prevention of vascular disease should not deter enthusiasm for the use of established preventive therapies, especially lifestyle measures.