January 9, 2019

expert reaction to HRT and blood clots

Research published in the BMJ demonstrates that most orally administered hormone replacement therapies were found to be associated with increased venous thromboembolism risks.

Professor Mary-Ann Lumsden, Spokesperson for the Royal College of Obstetricians and Gynaecologists:

“The findings from this large study add to the existing evidence on the link between different types of hormone replacement therapy (HRT) and risk of blood clots in women.

“It has been known for a long time that when taken as an oral tablet, HRT can increase risk of developing a blood clot and this increase depends on the type of oestrogen as well as the dose, with higher doses having a greater impact. This is not the case when HRT is taken as a patch or gel through the skin. Also, the findings clearly demonstrate that progestogen type is important.

“For women with a higher risk of blood clots, HRT may still be an option. Women should discuss this with their healthcare professional, as careful choice of regimen can minimise the increase in risk. For those at increased risk, transdermal HRT is likely to be the preferred option.

“The overall increase in risk of blood clot with HRT is small, but it is very useful to have results showing the risk associated with each HRT type as it will help to inform discussions between a woman and her healthcare professional. The decision whether to use HRT should be made by a woman who has been given clear, evidence-based information and who should consider other major risk factors for blood clots such as smoking or obesity. HRT dosage, regimen and duration should be individualised based on a woman’s medical history, family history and symptoms.”

Dr Channa Jayasena, member of the Society for Endocrinology and Senior Clinical Lecturer in Endocrinology at Imperial College London, said:

“We know that HRT has important benefits to alleviate menopausal symptoms. All drugs have side effects. It is widely accepted that HRT slightly increases blood clot risk in women. The authors have analysed data held by GPs on 80,000 women in the UK. This helpful study allows us to see which types of HRT have the highest and lowest risk of blood clots. HRT patches have the lowest risk of blood clots, and should be first-choice for older women (for whom blood clot risk is highest). However the study should reassure women that blood clots are an uncommon complication of HRT, regardless of the preparation.”

Prof Dame Valerie Beral FRS, Professor of Epidemiology and Director of Cancer Epidemiology Unit, University of Oxford, said:

“There is nothing new in these findings. Similar results have been published by others over the last decade. They confirm what is already known in the scientific literature and by regulatory bodies.”

‘Use of hormone replacement therapy and risk of venous thromboembolism: nested case-control studies using the QResearch and CPRD databases’ by Yana Vinogradova et al. was published in BMJ at 23:30 UK time on Wednesday 9th January 2019.

All our previous output on this subject can be seen at this weblink: http://www.sciencemediacentre.org/tag/hrt-menopause/

Declared interests

Dr Channa Jayasena: No conflicts of interest

None others received.