23 May 2008

Oral HRT 'Doubles' Blood Clot Risk, Says Study

Oral HRT doubles the risk of blood clots, according to a study by the British Medical Journal (BMJ).

Hormone replacement therapy (HRT), is regularly prescribed to women suffering from the effects of the menopause.

Previous studies have shown that taking HRT is associated with an increased risk of venous thromboembolism (VTE), a blood clot in the vein, which can be fatal.

Authors of the study reviewed data from eight observational studies and nine randomised controlled trials.

They found that women taking the oral form of the drug were between two and three times more likely to develop a blood clot and that the risk was significantly higher during the first year of treatment.

HRT given in patch form showed no significant increase in the risk of VTE, although the authors warned that the "results should be treated with caution as the data is from observational studies".

Overall, the results suggest that HRT patches might be safer that oral HRT with regards to thrombotic risk.

However, more research is needed to confirm the safety of oestrogen patches.

Helen Roberts from the University of Auckland said: "In the meantime, we can advise healthy menopausal women, aged 50–59, that the risk of VTE with oral preparations is 11 additional cases per 10 000 women per year for combined therapy and 2 additional cases per 10 000 women per year for oestrogen only."

The average age of menopause in the UK is 51. It occurs when women's ovaries make less of the female hormone oestrogen.

About 70% of women suffer physical symptoms around the time of the menopause.

In March this year, the BBC reported that a study conducted by the Institute of Psychiatry at King's College London found that HRT may reduce the risk of Alzheimer's.

(DS)