Hormone therapy carries risk of slight BP elevations in hypertensive postmenopausal women

The use of hormone therapy (HT) poses a small but significant increase in systolic blood pressure (BP) in postmenopausal women with hypertension, a study has found. However, this BP elevation does not lead to increased BP-lowering medication use over time.

Researchers performed a secondary analysis of the Women's Health Initiative HT clinical trials, which tested the effects of HT (conjugated equine oestrogens [CEE; 0.625 mg/d] or CEE plus medroxyprogesterone acetate [MPA; 2.5 mg/d]) on the risks for coronary heart disease and invasive breast cancer in women aged 50–79 years.

A total of 9,332 women with hypertension at baseline were included in the analysis. BP was assessed at baseline and up to 10 annual follow-up visits during the planned study phase. Antihypertensive medication use was also recorded at baseline and years 1, 3, 6, and 9 during the study, as well as during extended follow-up, which occurred at e median of 13 and 16 years after randomization. The researchers estimated the intervention effect through year 6.

During the intervention phase, participants on CEE alone had markedly higher systolic BP than those on placebo (mean difference, 0.9 mm Hg, 95 percent confidence interval [CI], 0.2–1.5 mm Hg; p=0.02). The same was true for participants on CEE plus MPA (mean difference vs placebo, 1.8 mm Hg, 95 percent CI, 1.2–2.5; p<0.001).

Results were consistent throughout the cumulative follow-up. Systolic BP was higher by a mean of 0.8-mm Hg (95 percent CI, 0.1–1.4) with CEE and by a mean of 1.6 mm Hg (95 percent CI, 1.0–2.3) with CEE plus MPA relative to placebo (p=0.02 and p<0.001, respectively).

Nevertheless, the mean number of antihypertensive medications taken at each follow-up visit remained stable between randomization groups during the intervention phase and the long-term extended follow-up of 16 years.