Hormone Replacement Therapy May Cause Increased Risk Of Stroke

Evidence published in the Cochrane Library has revealed that hormone replacement therapy (HRT) does not protect post-menopausal women against cardiovascular disease, and may even cause an increased risk of stroke.

While HRT is used widely for controlling menopausal symptoms, it has also been used to prevent cardiovascular disease in post-menopausal women.

The new evidence regarded the effects of using HRT for at least six months, involving more than 40,000 women around the world.

Treatment time for participants varied from seven months to just over 10 years.

Overall, the results gave no evidence that hormone replacement therapy provides effects against death from any cause, specifically cardiovascular disease, non-fatal heart attacks or angina in health women or women with pre-existing heart disease.

Findings actually revealed a small increased risk of stroke for post-menopausal women - the study's authors found that women who started treatment within the first 10 years of their menopause, when menopausal symptoms are most common, seem to have a small protection against death and heart attacks, and no increased risk of stroke. But in this group, the risk of deep vein thrombosis (DVT) increased.

Study author and the University of Oxford's Department of Cardiovascular Medicine's Dr Henry Boardman said the harms and benefits of hormone therapy vary according to the age of the woman, when they started their treatment.

"The evidence we have provides some support for the so-called 'Timing Hypothesis', but we should bear in mind the size of this effect," Dr Boardman said.

"When we looked at the results according to the age of women, or by how long since their menopause that they started treatment, we found that if 1000 women under 60 years old started hormone therapy we would expect six fewer deaths, eight fewer cases of heart disease and five extra blood clots over about seven years, compared to a 1000 similar women who did not start hormone therapy.

"The findings of this Cochrane review need to be carefully considered. This is a complicated health issue, where the same treatment offers benefits in some women, but harms in others."

The Cochrane Library Editor in Chief Dr David Tovey said the review added to the "complicated jigsaw" of HRT use to treat menopause symptoms.

"The main analysis that the authors did, found no benefit and so we need to apply caution to the results from the subgroup analysis. However if true, this apparent benefit in preventing heart disease in younger women should be considered alongside other possible benefits and emerging evidence of harms, including the risk of breast cancer, ovarian cancer, and DVT," Dr Tovey said.

Dr Boardman said: "Hormone therapy remains a valid treatment option for women who are significantly troubled by menopausal symptoms, however the risks and benefits of such treatment vary according to age and medical history. Discussion with your GP is recommended when considering treatment."