A Dangerous Treatment? Possible Link Found Between Hormone Therapy And Increased Stroke Risk

Hormone therapy in the treatment of symptoms of menopause has come under close scrutiny in a wide-ranging study conducted by a federal health agency.


The National Institutes of Health (NIH) has stopped the estrogen-only phase of the Women’s Health Initiative (WHI) — a large study of post-menopausal hormone therapy (PHT) using a combination of estrogen plus progestin — after finding an increased risk of stroke and no reduction in the risk of heart disease in post-menopausal women who have had a hysterectomy.

“The Women’s Health Initiative has been a landmark study that has provided important information about heart disease in women,” said Dr. Augustus O. Grant, president of the American Heart Association. “These new results from the WHI provide an additional rationale for the use of the AHA’s guidelines for cardiovascular disease prevention in women, released earlier this year.”

Previously, in 2002, the combination estrogen-plus-progestin arm of WHI was stopped early because of an increase in breast cancer in patients on active medication. That arm of the study suggested that estrogen plus progestin significantly increases the risk of invasive breast cancer and blood clots in the legs and lungs, yet does not protect women from heart disease and stroke. In fact, the study showed that women taking this drug had a higher risk of heart attack and stroke.

The AHA noted in its new guidelines that combined hormone therapy is not recommended for the prevention of heart disease and stroke, and instead recommended a conservative approach to the use of estrogen-alone hormone therapy until further research is available to support its use for cardiovascular disease prevention.

Moving Forward

The new WHI findings, Grant said, reinforce the AHA’s recommendation, adding that the use of hormone therapy for other reasons should be cautiously considered with the advice of a physician. Hormones may relieve menopausal symptoms, he said, but women should weigh the potential risks of therapy against the potential benefits for menopausal symptom control.

“This study by the Women’s Health Initiative underscores how important it is for women and their health care providers to follow the new guidelines for the prevention of cardiovascular disease in women,” said Dr. Lori Mosca, chair of the guidelines-writing group and director of Preventive Cardiology at New York-Presbyterian Hospital/Columbia Univer-sity Medical Center. She stressed the risk factors related to lifestyle.

“Although taking hormone therapy is not useful to prevent heart disease, these guidelines provide many other proven methods of lowering a woman’s risk, such as stopping smoking, controlling blood pressure and cholesterol levels, staying physically active and lean, and adding medications with a demonstrated benefit in women who are at specific levels of personal risk for heart disease or stroke.”

The earlier WHI study of combination hormone therapy found that women taking estrogen and progestin had an average of eight more strokes per year for every 10,000 women than those taking placebo.
The hormone-therapy findings have caused some alarm among women, which is why the NIH has prepared a series of questions and answers to provide some perspective.

What if I’m taking or considering taking estrogen alone, or estrogen plus progestin, to prevent heart disease or stroke?

Estrogen alone and estrogen plus progestin should not be used to prevent heart disease or stroke. Many established methods are available to lower heart disease risk in women. Lowering cholesterol and controlling blood pressure are two examples. If blood pressure and cholesterol aren’t controlled with lifestyle measures such as not smoking, getting regular physical activity, and eating a heart-healthy diet, then drug therapy may be indicated. Certain medications, such as aspirin, statins, beta blockers, and ACE inhibitors, also may benefit women who have cardiovascular disease or are at high risk of developing it.

What if I’m taking another type of hormone therapy to prevent heart disease or stroke?

Until there’s clear evidence that other forms of PHT not tested in recent clinical trials are beneficial, women should not use these therapies to prevent heart disease and stroke. Newer estrogen therapies, such as selective estrogen receptor modulators, aren’t the same as PHT. They don’t treat menopausal symptoms and don’t seem to increase the risk of breast cancer — but they are effective in treating osteoporosis and preventing fractures. Studies are under way to find out if they lower the risk of heart disease. However, like estrogen plus progestin, these should not be used for this purpose until more research is available.

What if I’m taking hormone therapy for other reasons, such as relief of menopausal symptoms?

For many women, using estrogen alone or estrogen plus progestin for short-term relief of menopausal symptoms may be worth the small absolute increase in risk for heart disease, stroke, or breast cancer. Because the risk of these complications rises the longer it is used, PHT should be used for the shortest time necessary. Women who’ve had premature menopause because their ovaries were surgically removed should consult their physicians about when to stop hormone therapy.

What if I’m taking hormone therapy to prevent osteoporosis?

Estrogen alone and estrogen plus progestin are effective for preventing osteoporosis and bone breaks, but these benefits may not outweigh the risk of breast cancer and cardiovascular disease. Other options should be considered.

Is more research under way to evaluate using other forms of hormone therapy to prevent and treat heart disease?

Yes. The WHI results show that postmenopausal hormone therapy didn’t work the way physicians assumed it would. This shows why studies like the WHI are so important. It also makes scientists more intent than ever to discover new types of estrogens that might help prevent and treat heart diseases.

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