Large Study Confirms Heart Attack Risk for Women on Hormone Replacement

New research on the association between Hormone Replacement Therapy (HRT) and heart attacks has been published online by Europe’s leading cardiology journal, the European Heart Journal. The study is the largest to look at the effects of HRT since the Women’s Health Initiative trial was stopped early after finding that HRT increased the risk of women developing a range of conditions including breast cancer and other health risks.

In this study, it appears that it is not so much the HRT that is the problem for women with heart attacks, it is the way that the hormone regimen is taken.

The research is a study of nearly 700,000 healthy Danish women, aged 51-69, who were followed between 1995-2001. The study found that in younger women (aged 51-54), their risk of heart attacks was 24% higher than in women who had never taken HRT. In addition, in younger women there was an increasing risk of heart attack the longer the HRT continued, which was not seen in the older age groups.

The study found that the type of HRT and the way that the women took it made a difference to the risk of heart attacks. Continuous HRT (a continuous combination of estrogen and progesterone) carried a 35% increased risk of heart attacks compared with women who had never used HRT. But if HRT was taken on a cyclical basis (estrogen, followed by a combination of estrogen and progesterone) there was a tendency for these women to have a reduced risk of heart attack. If the method of taking the estrogen was via a patch or gel on the skin or in the vagina, the risk of heart attack was reduced by more than a third (38% and 44% respectively).

Dr Ellen Løkkegaard, an MD who led the study at the Rigshospitalet in Copenhagen, Denmark, said: “Our study does not change indications and duration recommendations for HRT. But the main message is that when hormone therapy is indicated for a woman, then a cyclic combined regimen should be preferred, and that application via the skin or the vagina is associated with decreased risks."

Since the WHI trial was stopped, no further randomized controlled trials of HRT have been started.

Dave