HRT risks known by drug companies five years before public

Drug companies knew about the health risks surrounding hormone replacement therapy (HRT) five years before the public were informed.

Drug companies knew about the health risks surrounding hormone replacement therapy (HRT) five years before the public were informed.

Thousands of women may have been put at unnecessary risk because they were involved in HRT trials when experts knew that the menopause treatments increased the risk of heart disease. But the data, collated by the drug companies for licensing applications for their HRT products, was kept secret and not published.

Experts who tried to raise concerns about HRT were "ridiculed", according to an article in the British Medical Journal today. Researchers say the HRT case exposes the "strong vested interests and biased reporting" in the way drugs are licensed and tested by pharmaceutical companies.

Experts from the Nuffield Department of Obstetrics and Gynaecology at Oxford University conducted a study as early as 1997, which found there was a significantly increased risk of heart disease among women who took HRT. The 1997 research looked at 23 trials involving more than 2,000 women on HRT. But experts and drugs companies dismissed the study and insisted that the therapies were safe.

When the researchers tried to follow up their study by looking at unpublished data collated by the pharmaceutical companies for licensing applications, they hit a brick wall. Experts told them it would be impossible to obtain such data in Britain, and they had to go to the High Court in Finland to retrieve the details.

The researchers, having finally obtained six unpublished studies, found that the health risks associated with HRT were greater than they had initially thought. But only 4 per cent of the studies had adequate records of adverse events associated with HRT, and the researchers had to pore over complicated data sheets to extract the evidence.

Even then, the risks were ignored until 2002, when the Women's Health Initiative (WHI) study - involving 16,000 patients - was halted five years early because researchers concluded that the risks of HRT meant it would be unethical to continue. The WHI study showed that women on HRT had a 29 per cent increased risk of having a heart attack and a 41 per cent increased risk of suffering a stroke. The British-based Million Women Study into HRT was also halted as a result.

Thousands of women stopped taking HRT because of the health scare. Professor Klim McPherson, one of the Nuffield researchers, said: "The enthusiasm [of the drugs companies for HRT] was based on a leap of faith." He added that pharmaceutical companies should be forced to publish the results of studies they conduct on new drugs and treatments.

Although the HRT trials were stopped at an early stage, Professor McPherson said that many participants were needlessly exposed to the risk of heart disease and cancer. "These trials might not have been so necessary if better use had been made of existing evidence," he said. "How long will it take us to learn? How many women were needlessly exposed to an increased risk of cardiovascular disease?"

The latest revelations will add to the confusion surrounding HRT and the health risks associated with it. A leading researcher from the WHI study said this month that up to one-third of women who had abandoned HRT treatment had done so unnecessarily because they and their doctors had misunderstood the concerns. Susan Johnson said that, for women with severe menopausal symptoms, the benefits of HRT therapy still outweighed the risks.