Update on the cardiovascular risks of hormone replacement therapy

Area of Science:

• Cardiovascular Medicine
• Endocrinology
• Pharmacology

Background:

• Systematic reviews indicate hormone replacement therapy (HRT) use in women elevates cardiovascular disease risk.
• This risk encompasses venous thromboembolism, stroke, and coronary heart disease, with potential for peripheral arterial disease.

Purpose of the Study:

• To synthesize evidence on HRT's cardiovascular risks.
• To compare risks between different HRT formulations and patient demographics.

Main Methods:

• Systematic reviews of randomized controlled trials (RCTs).
• Meta-analysis of individual participant data from reported RCTs is recommended for further research.

Main Results:

• HRT increases total cardiovascular disease risk, with risks similar in relative terms to combined oral contraceptives but higher in absolute terms for HRT users due to age.
• Increased risk is associated with current use, advancing age, obesity, and potentially preparation type; transdermal HRT may have a lower venous thromboembolism risk than oral HRT.
• Activated blood coagulation is the probable mechanism; women with thrombophilias have higher venous thromboembolism risk, though screening utility is unproven.

Conclusions:

• HRT use is associated with increased cardiovascular risks, particularly in specific subgroups.
• Further research, including individual participant meta-analyses, is needed to fully elucidate risks across diverse populations and HRT types.