Growing doubts over reliability of HRT trial conclusions
pharmafile | July 6, 2004 | News story | |
Influential publicly-funded trials into HRT which convinced millions of women to stop taking the treatment could be flawed, researchers from US university Yale have suggested.
The Women's Health Initiative (WHI) study, involving 16,000 women, had found HRT increased the risk of heart attacks and strokes, but Yale scientists, led by Dr Frederick Naftolin, have questioned the findings, saying the study could not have detected any cardioprotective benefits as they didn't gather data on the group of women most likely to benefit from treatment.
The study, funded by the US government National Institutes of Health was halted in July 2002 when it found the risks of developing strokes and cardiovascular disease for women taking the combined oestrogen and progestogen (Wyeth's Prempro) HRT treatments outweighed the benefits.
Some separate research has in fact shown a reduced risk of heart attacks and stroke in women taking combined or oestrogen-only treatment – this positive effect was lost, however, if treatment was delayed until years after menopause.
The researchers, reporting in June's issue of Fertility and Sterility determined that the WHI would not have detected this effect because even the younger women participating in the trials were likely to have been well past menopause – the majority of women studied being in their 60s and 70s with an average age of 63.
"The Women's Health Initiative has been tremendously illuminating and, as we continue to consider the data it generated, questions continue to arise. The effects of hormone therapy on the health of a woman in her 40s just beginning the menopausal transition will be different from its effects on a woman 15 years older.
"We need prospective, randomised clinical trials starting during the menopausal transition to elucidate these differences so we can better tailor treatments to our patients' needs," said Marian Damewood, MD, president of the American Society for Reproductive Medicine.
Dr John Stevenson, of the British Menopause Society told the BBC: "We had two reasons to give HRT; for relief of menopausal symptoms and for the prevention of osteoporosis.
"We knew that there was a small risk of breast cancer and a very, very small risk of blood clots, but the benefits far outweighed the risks. And nothing has changed at all.
"This whole issue has been a huge disservice to women. Women have suffered unnecessarily because of this."
The Yale team concluded it would be wrong to dismiss the idea that HRT could prevent heart attacks and stroke and said more research was needed to isolate the exact effect on heart disease.
The news may offer some consolation to a beleaguered Wyeth whose global sales of Prempro fell by 32% last year.
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