For decades now, women navigating menopause have been buffeted by shifting research findings on the risks and possible benefits of hormone-replacement therapy. Now, a landmark clinical trial that followed more than 27,000 subjects for roughly 18 years has offered some conclusive evidence that neither the hype nor the grim warnings about hormone-replacement therapy were warranted.
In findings published Tuesday in the journal JAMA, women who were randomly assigned to take some form of hormone-replacement therapy for a median of six to seven years were no more, nor less, likely to die of any cause over the study's duration than were women who had been assigned to receive a placebo treatment.
The women who got synthetic estrogen and progesterone hormones to replace their naturally declining levels were no more (nor less) likely than those who got a placebo to die of stroke or heart failure. And they were neither more nor less likely to die of cardiovascular disease or cancer.
University of Pittsburgh Dr. Melissa McNeil, who wrote an editorial appearing alongside the new findings, called them "both compelling and reassuring."
For women who enter menopause early, whose bones are at high risk of fracture, or who suffer menopause-related hot flashes, night sweats and sleep disruption, "hormone therapy appears to be both safe and efficacious," wrote McNeil, who directs the comprehensive women's health program at Pitt's general internal medicine division.
The findings come from the Women's Health Initiative's hormone therapy trials, which were launched to assess the benefits and risks to mostly healthy post-menopausal women of taking hormone-replacement pills in a bid to reduce their risk of developing such cardiovascular and other chronic diseases. The study's 27,347 subjects averaged about 63 years old when they joined the study.
The Women's Health Initiative has been the source of a number of findings on the safety of hormone replacement therapy, many of them more perplexing than enlightening. In 2002 and 2004, its findings raised concerns that HRT would increase women's risk of heart disease, stroke and breast cancer.
Those findings would eventually lead to safer hormone combinations and a better understanding of who should consider HRT and when it should be initiated. But they would also slow a gathering stampede of menopausal women toward HRT and discourage many who could benefit from the treatment from considering it.
The latest trial results compared the death rates of 13,531 women who were assigned to take a placebo treatment to those of menopausal women who got one of two different forms of hormone-replacement therapy: 8,506 women — mostly those with an intact uterus — were assigned to get a combination of estrogen and progestin, and 5,310 — most of whom had undergone hysterectomy — got estrogen alone. (For women with an intact uterus, progestin was widely added to HRT regimens in the 1980s and '90s after researchers found that estrogen-alone regimens increased rates of endometrial cancers in such women.)
Over the trial's 18 years of follow-up, 7,489 of the women died. But whether researchers looked at death-from-any-cause, or deaths due to cancer, heart disease or stroke, the distribution of deaths in the trial's various arms showed no statistically significant differences.
While those findings will probably reassure women who have avoided taking replacement hormones for menopausal symptoms, they are likely as well to temper claims that HRT can help women reduce their risk of certain diseases and prolong life.
The findings, the new study's authors flatly wrote, "would not support use of hormone therapy for reducing chronic disease or mortality."
The results of the new trial, which represents the largest and most comprehensive study to assess HRT's effects, are in line with a position statement on HRT issued in June of this year by the North American Menopause Society.
That statement — the product of a comprehensive review of research by NAMS leaders — concluded that for most women who initiate hormone replacement therapy under 60, or within 10 years of reaching menopause, it's safe and can improve quality of life, increase productivity and reduce medical expenditures linked to untreated symptoms of menopause.
"This study is just one more piece of reassuring data in line with our findings," said Dr. JoAnn V. Pinkerton, professor of obstetrics and gynecology at the University of Virginia Health Center and chair of the NAMS panel that drafted that position statement.
In the wake of the first Women's Health Initiative findings issued 15 years ago, said Pinkerton, "fear drove women's decisions" on HRT. That should now change, she added — especially since safer and lower-dose HRT formulations are now available to women.
Pinkerton, who was not involved in the new research, acknowledged that women should not initiate hormone replacement therapy in hopes of fending off heart disease, dementia or osteoporosis. But despite the current study's failure to find survival benefits in those who took HRT, Pinkerton said women who are considering treatment because they're troubled by hot flashes and menopausal symptoms should know they might get some protection.
"There's a critical window" during which other research suggests the initiation of hormone replacement "appears to have benefits for heart, brain and bone," Pinkerton said.
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