The long-term effects of low-dose 17beta-estradiol and dydrogesterone hormone replacement therapy on 24-h ambulatory blood pressure in hypertensive postmenopausal women: a 1-year randomized, prospective study.

OBJECTIVE: The aim of this study was to assess the long-term effects of low-dose oral hormone replacement therapy (HRT) on 24-h blood pressure in hypertensive postmenopausal women. STUDY DESIGN: In this 12-month, prospective study, 66 postmenopausal women with mild or moderate hypertension were randomly assigned to receive either HRT with 1 mg/day micronized 17beta-estradiol sequentially combined with 10 mg/day dydrogesterone for 14 days of each 28-day cycle, or no therapy. Ambulatory blood pressure measurements were recorded for a 24-h period at baseline and after 12 months of treatment or follow-up. RESULTS: Blood pressure did not differ significantly between the groups at baseline. After 12 months, there were falls in 24-h systolic, diastolic and mean arterial blood pressure in both the HRT and control groups; only the fall in mean arterial blood pressure in the HRT group achieved statistical significance (-2.0 +/- 0.8 mmHg, p < 0.01). While there was no significant decrease in daytime systolic or mean arterial blood pressure in either group, a significant decrease in diastolic blood pressure (-1.8 +/- 10 mmHg, p < 0.001) was observed in the HRT group. Night-time systolic and mean arterial blood pressure also decreased significantly (p < 0.001) in the HRT group (-3.0 +/- 1.5 mmHg and -2.2 +/- 0.6 mmHg, respectively), but no significant change was observed in the control group. Conclusion: Low-dose oral HRT caused significant falls in both daytime and night-time ambulatory blood pressure in postmenopausal women with mild or moderate hypertension.