Portland, Ore.Two new systematic reviews of a broad spectrum of research on hormone replacement therapy (HRT) to prevent cardiovascular disease and other long-term health problems support the findings of a recently halted clinical trial in the Women's Health Initiative (WHI). These reviews were developed for the U.S. Preventive Services Task Force as background for new recommendations on HRT use that will be published in the fall for clinicians and patients.
The two reviews, one in the Aug. 20 Annals of Internal Medicine and the other in the Aug. 21 Journal of the American Medical Association (JAMA), found that for women taking HRT for five years or longer to prevent chronic conditions, the harm could exceed the benefit. The reviews were not able to determine whether the harms or benefits depended on types of hormones used. Although one study of estrogen and progestin in the WHI was stopped after five years because harms exceeded benefits, a second study of estrogen alone for women who have had a hysterectomy is continuing because the balance of benefits and harms is not yet clear.
The reviews were funded by the Agency for Healthcare Research and Quality (AHRQ), which sponsors the Task Force, and researched by the Evidence-based Practice Center at Oregon Health & Science University. Data from the WHI trial that was released last month were incorporated into the Annals and JAMA articles in an effort to integrate those results with systematic reviews of thousands of studies published on HRT since 1966. The Task Force, an independent panel of medical experts, will be reviewing these new systematic reviews in the next few months to update its 1996 recommendations on HRT.
The Annals article primarily addresses cardiovascular disease, and the JAMA article is an overall summary of the risks and benefits of HRT. The reviews did not examine the use of HRT to treat menopausal symptoms or specific pre-existing conditions such as osteoporosis.
The analyses revealed that there is good evidence to support the use of HRT to prevent bone fractures and less support for colon cancer prevention. Long-term HRT use appears to create a greater risk for stroke, blood clots, breast cancer and perhaps gall bladder disease. Also, new evidence suggests that HRT does not reduce the risk of heart disease and may modestly increase risk. However, the studies also show that despite increased risk for these various conditions, there is no overall greater mortality among HRT users.
"In light of recent publicity about the use of hormone replacement therapy, it's important to present the scientific evidence evaluating this treatment," said JAMA study author Heidi D. Nelson, M.D., M.P.H., associate professor in the OHSU School of Medicine and co-director of the Evidence-based Practice Center at OHSU. "These reports represent the first step in presenting this information. The next step will be the Task Force recommendations this fall."
The U.S. Preventive Services Task Force, the leading independent panel of private-sector experts in prevention and primary care, conducts rigorous, impartial assessments of all the scientific evidence for a broad range of preventive services. Its recommendations are considered the gold standard for clinical preventive services. The Department of Health and Human Services is leading the federal government's effort to ensure that clinicians and patients have the latest available scientific evidence on HRT use.
The published reviews were conducted by research teams at the Evidence-based Practice Center at OHSU. Linda Humphrey, M.D., M.P.H., associate professor in the OHSU School of Medicine, led the team that researched the Annals article on HRT and cardiovascular disease.