To treat severe hot flashes and other menopause symptoms, women may receive hormone replacement therapy. Some approaches, however, may pose lower heart risks than others.
After the Women's Health Initiative (WHI) released a study in 2002 linking hormone replacement therapy with increased heart disease and stroke risk, many women rejected any type of hormone treatment.
New research has found, however, that certain hormone therapies taken through a patch and in low doses may be less harmful to the heart than others.
Chrisandra Shufelt, MD, director of the Women's Hormone and Menopause Program at the Barbra Streisand Women's Heart Center in the Cedars-Sinai Heart Institute in Los Angeles, and a team of investigators reviewed the data on 93,676 post-menopausal women collected by the WHI.
Conducted at 40 sites in the United States, this multicenter study included patients ages 50 to 79.
Most women go through menopause (a time in their lives when periods permanently stop) after age 45. During this time, the ovaries stop producing the hormones estrogen and progesterone, and women may experience a range of symptoms, including hot flashes, night sweats, trouble sleeping, mood swings and difficulty focusing.
To alleviate severe symptoms, menopausal women may take hormone replacement treatment.
After tracking the use of hormone therapy by patients in this study, Dr. Shufelt and colleagues observed that women orally taking low doses of bioidentical forms of estrogen (estradiol) may have a slightly lower risk of stroke compared to those taking synthetic hormones, such as Premarin.
Bioidentical hormones are identical on a molecular level to the body’s own hormones, while synthetic hormones have a different chemical structure from those found naturally in the body.
Premarin is a conjugated equine estrogen (CEE) because it is made from pregnant mares’ urine, giving it a different structure from a woman’s natural hormone.
Sarah Samaan, MD, cardiologist and physician partner at the Baylor Heart Hospital in Plano, Texas, told dailyRx News that Premarin is the most commonly prescribed form of estrogen replacement in oral (pill) form. Estradiol, which is used in most patches and in pills such as Estrace and Ogen (derived from plant sources), is much more similar to a woman’s own natural estrogen.
This study also showed that taking estradiol via a patch on the skin (transdermally) was linked to a lower risk of heart disease compared with taking a CEE orally.
Oral estrogens pass through the liver, affecting proteins that may raise the risk of blood clots. Transdermal estrogens bypass the liver, entering the bloodstream directly.
“Several small studies suggest a higher risk for heart attacks, strokes and blood clots with Premarin when compared to other forms of oral estrogen,” Dr. Samaan to dailyRx News. “The patches and other topical forms of estrogen appear to be even safer. Unlike the estrogen pills, transdermal (patch or cream) estrogen will not raise triglyceride levels and is less likely to affect blood levels of CRP, a protein associated with inflammation.”
Dr. Samaan counsels her patients against the use of Premarin. “I generally advise that if estrogen replacement is required for menopausal symptoms, they should discuss the patch or cream with their gynecologist,” she said. “Some women feel better with the pills, and in those cases I advise estradiol.”
While the findings of this study are not conclusive and additional research is needed, Dr. Shufelt said that the results support previous investigations that have indicated that hormone therapy administered through a patch and in smaller doses may lower a woman's risk for developing cardiovascular disease compared to traditional hormone therapy.
The study was published online in September in the medical journal Menopause and will appear in the March 2014 print edition.