Increased Cardiovascular Risks from Some HRT Tablets
A recent study published in The BMJ has revealed that certain hormone replacement therapy (HRT) tablets, especially those containing both estrogen and progestogen, are associated with a higher risk of heart disease and rare but severe blood clots in women undergoing menopause. The study, conducted by researchers in Sweden, underscores the potential risks linked to popular HRT treatments used to manage menopausal symptoms, such as hot flashes and night sweats. While HRT can be effective in alleviating these symptoms, the findings suggest that different types of hormone therapy may have varying effects on cardiovascular health.
A Large-Scale Analysis of HRT and Cardiovascular Risks
The Swedish study examined the effects of contemporary hormone replacement therapy on cardiovascular disease by analyzing data from 138 emulated trials, which involved 919,614 women aged 50-58 between 2007 and 2020. These women had not used hormone therapy in the previous two years and were free from previous heart disease, cancer, or major surgeries, such as hysterectomies or ovary removal. The study tracked cardiovascular events over two years using hospital records and prescription data, with the aim of evaluating the risks associated with different types of HRT, considering both the route of administration and the hormone combinations used.
Women were assigned to one of eight treatment groups, including oral combined therapies (continuous and sequential), oral estrogen alone, tibolone, transdermal therapies, or no hormone therapy. The researchers monitored cardiovascular events, accounting for factors like age, blood pressure, diabetes, and education level.
Varied Risks with Different HRT Treatments
The study found that women who started oral combined continuous therapy or tibolone had an increased risk of ischemic heart disease, with approximately 11 new cases per 1,000 women annually. Tibolone, a synthetic steroid used in some HRT regimens, was also linked to a higher risk of heart disease, heart attacks, and strokes, although it did not appear to increase the risk of blood clots. In contrast, no increased risk of cardiovascular disease was observed with transdermal treatments, such as skin patches, gels, or creams, suggesting that these methods may be safer for some women.
The study also found that certain oral hormone replacement therapy treatments, including oral combined continuous therapy, oral combined sequential therapy, and oral unopposed estrogen, were associated with an elevated risk of venous thromboembolism (VTE), a potentially life-threatening condition involving blood clots. If 1,000 women started these treatments, about seven new cases of VTE could be expected each year. On the other hand, transdermal combined therapy was similarly linked to an increased risk of blood clots.
Calls for Further Research and Caution in HRT Use
While these findings offer important insights into the cardiovascular risks of HRT, the authors note that the study’s observational nature means no definitive conclusions about causality can be drawn. The study’s limitations include the lack of data on menopausal status and potential confounding factors, such as smoking and body mass index. However, the researchers believe the use of an emulated trial design helped reduce bias and improve the accuracy of their findings. They emphasize the need for future research to explore how different types of progestogens, a key component of many HRT therapies, affect cardiovascular risk.
This study highlights the diverse effects of various hormone combinations and delivery methods on cardiovascular health, encouraging women and healthcare providers to carefully consider the risks and benefits of different hormone replacement therapy options.
