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Hormone Replacement Therapy (HRT) and the
Risk of Cardiovascular Disease
For more than 50 million American women, and millions
of women in other countries who are over the age of 50, the decision
whether or not to use estrogen replacement therapy (ERT) to prevent
chronic diseases is often difficult. Established benefits of ERT therapy
for menopausal symptoms and prevention of osteoporosis must be weighed
against documented risk of therapy, including blood clots, gallbladder
disease and a possible risk of breast or uterine cancer.
For years, one of the cornerstones of preventive
medicine was the belief that estrogen protects the heart. In the years
before menopause, when women naturally produce estrogen, they are almost
immune to heart disease, but after menopause the heart disease risk for
women climbs until it equals that of men. Based on this observation, as
well as animal studies that demonstrated that estrogen had a beneficial
effect on blood vessels, experts believed that replacing estrogen after
menopause could reduce the risk of heart disease in older women.
When hormone replacement therapy was studied in a more
controlled setting among women who had heart attacks the findings were
surprising. Estrogen did not prevent a second heart attack but it appeared
to increase the risk of having one.
An earlier trial called the Heart and Estrogen/progestin
Replacement Study had shown the among women with heart disease, taking
oral estrogen plus progestin elevated the risk of recurrent heart problems
in the first year of use, then lowered it thereafter. To investigate this
trend further, researchers in one of the new studies analyzed 20 years
worth of data on nearly 2, 500 women in another large US trial. Overall,
the women who all had established heart disease saw their risk for hear
attack and death go up 25% in their first year on Hormone Replacement
Therapy (HRT), compared with those who had never used hormones. Women who
used HRT for more than one year experienced a drop in heart risk,
including a 62% decline among those on hormone for 2 or more years. These
findings suggest that hormone therapy increases the risk for a recurrent
coronary event in the short term and that hormone therapy should not be
started solely for the prevention of recurrent heart diseases.
A second study repeats these findings. The study,
reported in the July issue of the Journal of the American College of
Cardiology (JACC), involved nearly 1,900 postmenopausal women who had
suffered heart attacks. A team led by Dr. Karen P. Alexander of Duke
University in Durham, North Carolina, found that women who started HRT
after having a heart attack were 44% more likely those who never used HRT
to have another heart attack or die in the following year. Researches say
it is unclear why HRT presents a temporary risk to women with heart
disease but it may have a possible link to levels of C-reactive protein,
which is an inflammatory substance linked to heart diseases.
Although HRT is known to ease menopausal symptoms and
help prevent bone loss, it has also been linked to a slightly increased
risk of breast cancer. And while a number of studies have suggested that
women without prior heart problems can lower their risk of heart disease
with HRT, the therapy now appears risky for women with heart disease.
Although uncertainty remains, it appears that postmenopausal hormone
therapy should not be used for the purpose of preventing coronary artery
disease unless future well-designed studies demonstrate such benefit.
Instead, women interested in preventing heart disease should direct their
efforts toward lifestyle modification, which is proven to reduce the risk
of heart diseases. Such lifestyle changes are smoking cessation, weight
loss, regular exercise and lowering high blood pressure and high
cholesterol levels. |
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