Daily Dose: Postmenopausal Women Using Oral Estrogen Hormone Therapy More Likely to Develop HTN

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On June 15, 2023, we reported on a study published in Hypertension that examined the association between route of administration and formulation of estrogen hormone therapy (HT) and hypertension (HTN) risk in postmenopausal women.

The study

For the population-based study, researchers identified women aged ≥45 years who filled ≥2 consecutive prescriptions for estrogen-only HT as recorded in linked provincial health administrative databases in Alberta between 2008 and 2019. Incident HTN at least 1 year following initiation of treatment, identified via health records, was specified as the primary study outcome. Hazard ratios (HRs) for HTN in women using oral compared with transdermal, vaginal, or intramuscular HT were calculated using Cox proportional hazard models.

The findings

The final cohort included 112 240 women who used an estrogen-only form of HT. Authors found that the risk of developing HTN was 14% higher among women taking oral estrogen HT compared to those using transdermal estrogen and 19% higher compared to women using vaginal estrogen creams or suppositories. Further, in models adjusted for participant age, the association with HTN was stronger among those aged ≤70 years than those older than age 70.

When researchers analyzed the risk of HTN by type of estrogen, they found an increased risk associated with conjugated equine when compared with estradiol (HR, 1.08; 95% CI, 1.04–1.14) but not when compared to estrone (HR, 1.00; 95% CI, 0.93–1.10). The researchers also reported in the study findings that both duration of estrogen exposure and cumulative dose of estrogen were associated with an increased risk of HTN.

Clinical implications

"Oral estrogen-only HT use was associated with an increased risk of hypertension in women. In women using estrogen-only HT, nonoral estradiol at the lowest dose and for the shortest time-period is associated with the lowest risk of hypertension."

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