HRT pills linked to increase in clots and strokes
pharmafile | March 10, 2015 | News story | Research and Development, Sales and Marketing | Cochrane, HRT, boardman, hormone replacement therapy
HRT tablets do not offer heart benefits and slightly increase the risk of strokes and blood clots in some women.
A gold-standard systematic review by researchers from the Cochrane Heart Group combined the results of 19 randomised controlled trials comparing over 40,000 women with an average age of 60, who took tablet forms of hormone therapy with women who either took a placebo or no treatment, for a minimum of six months.
Unlike previous single trials, the pooled results found there was no protective benefit from taking HRT and it was not linked with a decreased risk of heart problems or death from heart disease. But there was a small increased risk of stroke from taking HRT tablets, as well as an increased risk of blood clots in the lungs or in the veins.
In absolute terms the numbers of women who had additional harmful outcomes from taking HRT was small. Compared to 1,000 similar women who did not take have the therapy, researchers calculated that for every 1,000 women who took HRT for four years there would be an average of six extra strokes. And on average for every 1,000 women there would be an extra eight blood clots every six years – and an additional four clots in the lungs every three years.
But the picture became more mixed when the researchers looked at a woman’s age or how long ago women had started taking treatment.
Women who started taking HRT less than 10 years after the menopause (or before the age of 60) had a lower risk of dying or having heart problems during the study, but a slightly higher risk of clots, compared to women on a placebo or those who didn’t take HRT. There was no link between starting HRT early and the chances of having a stroke.
On the other hand women who started HRT more than 10 years after the menopause did not have the mortality and heart risk benefit, and had an increased risk of stroke.
The researchers concluded: “Overall, the results showed no evidence that hormone therapy provides any protective effects against death from any cause, or death specifically from cardiovascular disease, non-fatal heart attack or angina, either in healthy women or women with pre-existing heart disease. Rather, in post-menopausal women hormone therapy increased the risk of stroke and obstruction of a vein by a blood clot.”
Dr Henry Boardman, from the department of cardiovascular medicine at the University of Oxford, says: “We should bear in mind the size of this effect. The findings 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 researchers also cautioned there was insufficient evidence from the studies to draw firm conclusions on the effects of the length of time of treatment. The trials only considered HRT tablets, so any possible risks associated with other forms of HRT, such as patches and gels, remains unclear.
Lilian Anekwe
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