Effect of hormone therapy on BP in normotensive and hypertensive postmenopausal women

High blood pressure (BP) ranks as the greatest risk factor for cardiovascular disease. The increased cardiovascular risk determined in recent interventional studies has led the health authorities in some countries to re-ignite the discussion about whether hypertension should be listed as a contraindication for hormone replacement therapy (HRT). We reviewed papers published since 1960 and listed in MEDLINE, EMBASE and Biosis, on studies that monitored the course of BP during HRT. We found that both primarily normotensive and hypertensive postmenopausal women actually run only a very low risk of BP increase during HRT, indeed, BP was often lowered. In one of our own studies 1397 hypertensive women with BP diastolic >95 mmHg received transdermal HRT regimens; BP was lowered by an average of 7 mmHg systolic and 9 mmHg diastolic. The results of the more recent 24-h ambulatory BP studies are particularly conclusive. At least 19 such studies have been performed, 13 placebo-controlled and 10 cross-over; 5 found no effect on BP and 14 studies demonstrated BP reductions. BP was lowered by treatment with transdermal estradiol in 11 of 13 studies and by oral estrogen in 4 of 11 studies. The effects were not consistent with regard to systolic or diastolic BP nor to action on day- and night-time BP. It cannot be ruled out that some women with a particular predisposition exhibit an abnormal reaction to the vasoactive effects of HRT, and there is a paucity of long-term data on risk populations, specifically on the progestogenic effects in patients with pre-existing arteriosclerotic lesions. In conclusion, the risk of developing hypertension during HRT is very low, but hormone therapy should always be appropriately indicated and during therapy BP should be checked regularly.