HRT tablets associated with increased risk of blood clots as opposed to other forms of therapy such as patches or gels.
Study: University of Nottingham published a study in January 2019 in the British Medical Journal.
A team from the University of Nottingham recently published a study in the British Medical Journal (BMJ) stating that the blood clot risk was highest in women who take HRT tablets as opposed to other forms of the therapy, such as patches or gels. This risk was also increased in women who took higher doses.
Headlines the past few years have warned women that hormone replacement therapy (HRT) can be linked to blood clots and stroke. The study conducted by the University of Nottingham found that there is no increased risk in other forms of the therapy which includes HRT administered via patches, topical creams and gels.
HRT is administered via tablets and transdermal treatments such as patches, topical creams and gels. Some HRT only contains estrogen (single drug), while other forms of the therapy require women have both estrogen and progesterone (combined drug). HRT can relieve menopause symptoms such as night sweats and hot flushes as well as reduce the risk for certain health conditions in women going through menopause.
The UK researchers hoped their research would give doctors more specifics to help determine the risk of blood clots, known medically as venous thromboembolism, in women who take HRT. They drew data from records of more than 2,000 practices from 1998 to 2017. Other relevant factors, such as lifestyle, family history of blood clots, and underlying conditions linked to blood clots were taken into account.
When they compared records of all women who developed blood clots with those who had not, they noted that women on HRT tablets were twice as likely to be at risk for blood clots. These women had a 70 percent risk for blood clots compared to those taking other forms of HRT.
The risk of blood clots was 15 percent higher in women on single and combined drug treatments for those taking natural estrogen that came from horse urine compared to synthetic estrogen.
Women using HRT in patch, gel, or cream form were not at increased risk for blood clots, even those taking higher doses of the medication. Interestingly, only 20% of HRT prescriptions were for non-oral treatments even though doctors know they pose a lower risk.
“Our findings are particularly important for women who require HRT treatment and are already at increased risk for developing blood clots,” said Yana Vinogradova, PhD, a statistician who conducted the research at the University’s school of medicine.
The researchers say these findings provide important information for women and their doctors to help them make the best treatment choices.
They suggest greater consideration should be given to transdermal HRT, particularly for women already at an increased VTE risk and in line with recent guidelines.
BMJ 2019; 364:k4810 (Published 09 January 2019) Use of hormone replacement therapy and risk of venous thromboembolism: nested case-control studies using the QResearch and CPRD databases. Accessed 6 March 2019 Available at: https://www.bmj.com/content/364/bmj.k4810