The effects of hormone therapy (HT) on mean and visit-to-visit variability (VVV) of blood pressure in postmenopausal women were recorded in the Women’s Health Initiative (WHI) randomized controlled trials . Blood pressure was measured at baseline and annually in the two WHI HT trials, in which 10,739 and 16, 608 postmenopausal women were randomized to conjugated equine estrogens (CEE, 0.625 mg/day) or placebo, and CEE plus medroxyprogesterone acetate (MPA, 2.5 mg/day) or placebo, respectively. At the first annual visit (year 1), the mean systolic blood pressure was 1.04 mmHg (95% confidence interval (CI) 0.58–1.50) and 1.35 mmHg (95% CI 0.99–1.72) higher in the CEE and CEE + MPA arms, respectively, compared with the mean systolic blood pressure in women taking the corresponding placebos. These effects remained stable after year 1. CEE also increased the VVV of systolic blood pressure (ratio of VVV in CEE vs. placebo, 1.03; [i]p [/i] < 0.001), whereas CEE + MPA did not (ratio of VVV in CEE + MPA vs. placebo, 1.01; [i]p [/i] = 0.20). After accounting for study drug adherence, the effects of CEE and CEE + MPA on mean systolic blood pressure increased at year 1, and the differences in the CEE and CEE + MPA arms vs. placebos also continued to increase after year 1. Further, both CEE and CEE + MPA significantly increased the VVV of systolic blood pressure (ratio of VVV in CEE vs. placebo, 1.04; [i]p [/i] < 0.001; ratio of VVV in CEE + MPA vs. placebo, 1.05; [i]p [/i] < 0.001).
Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel