New research suggests that while women with type 2 diabetes using HRT skin patches are not at a higher risk for blood clots or stroke, they may increase their risk for pulmonary embolism and heart disease overall if they take oral HRT.
MedicalNewsToday reports that HRT, which can ease menopausal symptoms, may include individual or combinations of the hormones oestrogen and progesterone, depending on a person’s needs, and is available in various forms, including tablets, gels, rings, injections and skin patches.
But just like any medication, some side effects and complications can occur.
For instance, past studies show that HRT may increase 'the risk for certain cancers, such as breast and endometrial cancer, as well as for cardiovascular events like blood clots, stroke and heart attack.
Research recently presented at the 2025 Annual Meeting of The European Association for the Study of Diabetes (EASD) reports that women with type 2 diabetes using HRT skin patches are not at a higher risk for blood clots or stroke.
However, the study did find that women with type 2 diabetes taking oral HRT may increase their risk for pulmonary embolism – when a blood clot forms in a lung artery – and heart disease overall.
This research is yet to appear in a peer-reviewed journal.
Oral HRT linked to pulmonary embolism
For this study, researchers analysed medical data from the TriNetX global database of more than 36 000 women with an average age of 59 from across the United States and Europe.
Participants were selected if they had started an HRT and statin – to help lower cholesterol levels – or just a statin prescription. They were followed for an average of five years to see if they developed pulmonary embolism, deep vein thrombosis (DVT), ischaemic heart disease, ischaemic stroke, or ovarian, breast, or endometrial cancers.
At the study’s conclusion, researchers found that participants with type 2 diabetes taking transdermal HRT via skin patches had a 25% lower risk of developing heart disease, and no difference in risk for pulmonary embolism, DVT, stroke, or cancer, compared with females with type 2 diabetes not taking HRT.
Yet when looking at participants with type 2 diabetes taking oral HRT, they had double the risk of developing a pulmonary embolism, and a 21% higher chance for heart disease, compared with participants taking transdermal HRT.
“Our study suggests that up to five years of regulator-approved doses of transdermal HRT appears safe in a large cohort of women in midlife with type 2 diabetes, and that the use of HRT skin patches is not associated with an excess increased risk of cardiovascular complications or oestrogen-sensitive cancers compared with women with type 2 diabetes who did not use HRT,” said Matthew Anson, PhD, clinical research fellow at the University of Liverpool and University Hospitals of Liverpool Group in the United Kingdom, and lead author of this study.
“However, given increased risks with oral HRT, we propose that women with type 2 diabetes should not be prescribed oral oestrogen therapy,” he added.
Who should worry about risks?
Jennifer Cheng, DO, chief of endocrinology at Hackensack Meridian Jersey Shore University Medical Centre in New Jersey, who was not involved in this research, said she found the study promising, that it highlights the need to recognise patients who may benefit from HRT or, on the contrary, whom this therapy may place at higher risk of certain health complications.
“We need to consider carefully, especially since women with type 2 diabetes may develop cardiac disease at high rates and do not have the typical symptoms for heart attacks,” she said. “Mitigating the risks would be welcome in these patients.”
She added that it was promising that patients receiving transdermal HRT have a reduced risk of ischaemic heart disease without increased risk of stroke or blood clots.
“Women with diabetes are concerned about cardiovascular risks since diabetes is cardiovascular risk equivalent – (meaning there is an) increased risk of heart disease. The study provides positive data showing we can treat menopausal symptoms with transdermal HRT without increased vascular risk, and potentially having cardiac benefits.”
Sherry Ross, MD, a board-certified OB/GYN and Women’s Health Expert at Providence Saint John’s Health Centre in Santa Monica, said that “with more than 100 disruptive symptoms of menopause, hormone therapy can change a person’s quality of life”.
“Women with type 2 diabetes must be counselled on the increased risks of pulmonary embolism, deep vein thrombosis, heart disease, and stroke when using hormone therapy. As doctors, it is our responsibility to ensure they use the transdermal form of oestrogen to decrease these dangerous risks …when compared with oral oestrogen,” said Ross, who was not involved in the study.
“There simply has not been enough research done on menopause and the safety profiles for women using hormone therapy, especially those with other medical complications.
“Larger, prospective studies, would help find other potential cardiovascular risks associated with different forms of hormone therapy,” Ross added. “There are many associated risks for heart disease, so separating out some of these common risk factors would help to understand the relationship between type 2 diabetes and hormone therapy formulations used to treat the disruptive symptoms of menopause.”
See more from MedicalBrief archives:
HRT women at ‘small’ risk of clots and stroke
Menopausal HRT linked to healthier heart
Hormone therapy for menopause symptoms: two decades on, the fear of risks persist