Some HRT Tablets May Be Linked to Increased Risk of Heart attack and Blood Clot: Study - Video

Certain hormone replacement therapy (HRT) tablets containing both oestrogen and progestogen are associated with a higher risk of heart disease and rare but serious blood clots known as venous thromboembolism (VTE) in women around the age of menopause, finds a study from Sweden published by The BMJ.

Another HRT tablet called tibolone was associated with an increased risk of heart disease, heart attack and stroke, but not blood clots, “highlighting the diverse effects of different hormone combinations and administration methods on the risk of

cardiovascular disease,” say the researchers.

Researchers set out to assess the effect of contemporary menopausal hormone therapy on the risk of cardiovascular disease according to the route of administration and combination of hormones.

Their findings are based on data from 138 emulated trials, involving 919,614 healthy women in Sweden aged 50-58 between 2007 and 2020 who had not used hormone therapy in the previous two years. They excluded women with a history of heart disease, stroke, narrowed arteries, or cancer, and who had undergone surgery to remove their ovaries, a hysterectomy, or sterilisation.

Using monthly prescription records, the women were assigned to one of eight menopausal hormone treatment groups: oral combined continuous, oral combined sequential, oral unopposed oestrogen, oral oestrogen with local progestin, tibolone, transdermal combined, transdermal unopposed oestrogen, or no menopausal hormone therapy.

Hospital records were then used to track cardiovascular events over two years, and other potentially influential factors such as age, education level, region of residence, high blood pressure and diabetes were taken into account. During this monitoring period, 24,089 cardiovascular events were recorded among the 919,614 women in the study.

Compared with not starting menopausal hormone therapy, starting oral combined continuous therapy or tibolone was associated with an increased risk of ischemic heart disease. This translates to approximately 11 new cases of ischaemic heart disease per 1,000 women who start treatment with oral combined continuous therapy or tibolone over one year. No increased risk of cardiovascular disease was found for transdermal treatments, which include skin patches, gels and creams.

An increased risk of blood clots was also found for oral combined continuous, oral combined sequential, oral unopposed oestrogen, and transdermal combined therapy. “If 1,000 women started each of these treatments and were observed for a year, we would expect to see seven new cases of venous thromboembolism across all groups,” say the authors.