Experts question research on HRT

MILLIONS of women may have been misled about the effect of hormone replacement therapy (HRT) on heart disease risk because of flawed research, experts claimed yesterday.

A new study has raised serious doubts over a pivotal US investigation that overturned preconceptions about HRT and the heart.

Scientists said the Women’s Health Initiative (WHI) study, which reversed many experts’ opinions about HRT, could not possibly have detected a beneficial effect on heart health given the way it was designed.

Previously it had been assumed that hormone replacement protected post-menopausal women from heart attacks and strokes.

But in 2002 the WHI showed that far from being protective, a common form of combined-hormone HRT actually increased the risk of both.

The chances of suffering a heart attack were raised by 29%, and of a stroke by 41%, while the risk of blood clots was doubled.

Breast cancer risk was also increased by 26% in women on HRT, although this finding was not unexpected.

Scientists were so alarmed by the results that the study, which involved more than 16,000 women, was terminated three years early.

As a direct consequence large numbers of women were scared away from HRT.

But the WHI researchers have been criticised for jumping to conclusions and ending the study prematurely.

The new research, led by Dr Frederick Naftolin from Yale University in Connecticut, cast a critical eye over the WHI study, focusing on the kind of women who took part in the investigation.

It concluded that the WHI was underpowered by a factor of 10 and would have had to enrol thousands more participants for its chief findings to have any statistical relevance.

At the core of the complaint is the fact that the vast majority of women recruited for the study were in their 60s and 70s and had not had a period for an average of 13 years.

But previous research had indicated that it was women in their early 50s just starting the menopause who seemed to gain protection against heart disease from HRT.

The scientists said the effect of HRT on heart disease risk remained an open question, and there was a vital need to investigate it further.