July 11, 2007 - If started long after menopause, hormone therapy carries serious risks for older women, a study from the U.K., Australia, and New Zealand shows.
The study, called the WISDOM (Women's International Study of Long Duration Oestrogen after Menopause), was very like the Women's Health Initiative (WHI) study:
- Both studies looked at Prempro (combined estrogen plus progesterone) or, for women who had hysterectomies, Premarin (estrogen alone).
- Both studies tested whether hormone therapy could be used to prevent disease in older women.
- Neither study tested hormone therapy for relief of menopausal symptoms.
- Women in both studies started or restarted hormone therapy years after menopause.
- Both studies were stopped when safety concerns became apparent in the Prempro arm of the WHI.
Because of it's early halt, the WISDOM trial followed women only for about a year after starting hormone therapy. Nevertheless, the trial found that hormone therapy has serious risks for older women (the average age of the 5,692 women in the trial was 63).
Researcher Janet H. Darbyshire, MB, is director of the clinical trials unit of the U.K. Medical Research Council, which sponsored the trial.
"There was no evidence of benefit, which we hoped there would be," Darbyshire tells WebMD. "Instead, there was an increase in risk of cardiovascular events."
Within the first year of the trial, 11 women had "cardiovascular events" -- that is, angina (chest pain), nonfatal heart attack, or sudden cardiac death. All of these women were assigned to hormone therapy. None of these serious events occurred among women receiving inactive placebo treatment.
By itself, the brief trial proves very little. But the findings are identical to those seen over seven years in the WHI study, Darbyshire says.
That's true, says JoAnn Manson, MD, DrPH, chief of preventive medicine at Harvard's Brigham and Women's Hospital in Boston. Manson is one of the principal researchers for the WHI and is co-author of the book Hot Flashes, Hormones, and Your Health.
"These findings from WISDOM are consistent with WHI," Manson tells WebMD. "In older women using these hormone formulations, the risk outweighs the benefits. There was evidence of increased cardiovascular disease and blood clots."
The bottom line, Manson and Darbyshire agree, is that hormone therapy should not be used for disease prevention.
Both experts also agree that the findings do not apply to the main use for hormone therapy: relief of severe menopausal symptoms.
"There is no one-size-fits-all solution to hormone therapy," Manson says. "The answer depends on the presence of menopausal symptoms that interfere with sleep and disrupt quality of life. And it depends on whether a woman is at risk of heart disease or stroke. If so, there is increased risk with hormone therapy."
"Hormone therapy is a two-edged sword. It seems to help the earliest stages of heart disease, but may increase the risk of blood clots and arterial plaque rupture if continued into older age," Manson says.
The WISDOM results appear in the July 11 online issue of the British medical journal BMJ.