Contemporary menopausal hormone therapy and thrombotic disease: nationwide nested case-control study

The study investigated the relationship between menopausal hormone therapy use and the occurrence of thromboembolism, ischaemic stroke, and myocardial infarction in women aged 50-69 years in Denmark between 2003-2021. The incidence of these conditions without hormone therapy was 15.8 to 20.3 cases per 10,000 women per year. Oral oestrogen therapy use was associated with increased risk of thromboembolism (1.6-fold), ischaemic stroke (1.3-fold), and myocardial infarction (1.2-fold). The absolute risk increase per year was 0.09% for thromboembolism, 0.06% for ischaemic stroke, and 0.03% for myocardial infarction. Higher doses of oral oestradiol (>1 mg/day) used for longer than one year showed increased risk, which increased with treatment duration. Transdermal therapy was not associated with increased thrombotic risk, with the exception of increased myocardial infarction risk with combined cyclic transdermal therapy.