Influence of 17beta-oestradiol on blood pressure of postmenopausal women at high vascular risk

The association of hormone therapy with blood pressure control in postmenopausal women with hypertension: a secondary analysis of the Women's Health Initiative clinical trials

OBJECTIVE

The objective of this study was to assess the effect of menopausal hormone therapy (HT) on blood pressure control in postmenopausal women with hypertension.

METHODS

The Women's Health Initiative HT clinical trials were double-blinded, randomized, placebo-controlled studies of women aged 50 to 79 years testing the effects of HT (conjugated equine estrogens [CEE, 0.625 mg/d] or CEE + medroxyprogesterone acetate [MPA; 2.5 mg/d]) on risks for coronary heart disease and invasive breast cancer, the primary outcomes for efficacy and safety, respectively. This secondary analysis of the Women's Health Initiative HT trials examined a subsample of 9,332 women with hypertension (reported ever taking pills to treat hypertension or were taking antihypertensive medication) at baseline. Blood pressure was measured at baseline and up to 10 annual follow-up visits during the planned study phase. Antihypertensive medications were inventoried at baseline and years 1, 3, 6, and 9 during the study, and self-reported during extended follow-up: 2009-2010 and 2012-2013, which occurred median of 13 and 16 years after randomization, respectively. The intervention effect was estimated through year 6. Cumulative follow-up included all visits.

RESULTS

Compared with placebo, CEE-alone had significantly ( P = 0.02) higher systolic blood pressure (SBP) by mean (95% confidene interval [CI]) = 0.9 (0.2-1.5) mm Hg during the intervention phase. For cumulative follow-up, the CEE arm was associated with increased SBP by mean (95% CI) = 0.8 (0.1-1.4) mm Hg ( P = 0.02). Furthermore, CEE + MPA relative to placebo was associated with increased SBP by mean (95% CI) = 1.8 (1.2-2.5) mm Hg during the intervention phase ( P < 0.001). For cumulative follow-up, the CEE + MPA arm was associated with increased SBP by mean (95% CI) = 1.6 (1.0-2.3) mm Hg ( P < 0.001). The mean number of antihypertensive medications taken at each follow-up visit did not differ between randomization groups during the intervention or long-term extended follow-up of 16 years.

CONCLUSION

There was a small but statistically significant increase in SBP in both CEE-alone and CEE + MPA arms compared with placebo during both the intervention and cumulative follow-up phases among postmenopausal women with hypertension at baseline. However, this increase in SBP was not associated with an increased antihypertensive medication use over time among women randomized to HT compared with placebo.

Menopausal hormone treatment cardiovascular disease: another look at an unresolved conundrum

Cardiovascular disease (CVD) is the most common cause of death in women. Before the Women's Health Initiative (WHI) hormone trials, evidence favored the concept that menopausal hormone treatment (MHT) protects against CVD. WHI studies failed to demonstrate CVD benefit, with worse net outcomes for MHT versus placebo in the population studied. We review evidence regarding the relationship between MHT and CVD with consideration of mechanisms and risk factors for atherogenesis and cardiac events, results of observational case-control and cohort studies, and outcomes of randomized trials. Estrogen effects on CVD risk factors favor delay or amelioration of atherosclerotic plaque development but may increase risk of acute events when at-risk plaque is present. Long-term observational studies have shown ∼40% reductions in risk of myocardial infarction and all-cause mortality. Analyses of data from randomized control trials other than the WHI show a ∼30% cardioprotective effect in recently menopausal women. Review of the literature as well as WHI data suggests that younger and/or more recently menopausal women may have a better risk-benefit ratio than older or remotely menopausal women and that CVD protection may only occur after >5 years; WHI women averaged 63 years of age (12 years postmenopausal) and few were studied for >6 years. Thus, a beneficial effect of long-term MHT on CVD and mortality is still an open question and is likely to remain controversial for the foreseeable future.

Sex-specific risk of cardiovascular disease and cognitive decline: pregnancy and menopause

Understanding the biology of sex differences is integral to personalized medicine. Cardiovascular disease and cognitive decline are two related conditions, with distinct sex differences in morbidity and clinical manifestations, response to treatments, and mortality. Although mortality from all-cause cardiovascular diseases has declined in women over the past five years, due in part to increased educational campaigns regarding the recognition of symptoms and application of treatment guidelines, the mortality in women still exceeds that of men. The physiological basis for these differences requires further research, with particular attention to two physiological conditions which are unique to women and associated with hormonal changes: pregnancy and menopause. Both conditions have the potential to impact life-long cardiovascular risk, including cerebrovascular function and cognition in women. This review draws on epidemiological, translational, clinical, and basic science studies to assess the impact of hypertensive pregnancy disorders on cardiovascular disease and cognitive function later in life, and examines the effects of post-menopausal hormone treatments on cardiovascular risk and cognition in midlife women. We suggest that hypertensive pregnancy disorders and menopause activate vascular components, i.e., vascular endothelium and blood elements, including platelets and leukocytes, to release cell-membrane derived microvesicles that are potential mediators of changes in cerebral blood flow, and may ultimately affect cognition in women as they age. Research into specific sex differences for these disease processes with attention to an individual's sex chromosomal complement and hormonal status is important and timely.

Timing and duration of menopausal hormone treatment may affect cardiovascular outcomes

Largely on the basis of the first publication of findings of net harm with menopausal hormone treatment in the Women's Health Initiative (WHI) hormone trials, current Food and Drug Administration recommendations limit menopausal hormone treatment to the "…shortest duration consistent with treatment goals…," with goals generally taken to mean relief of menopausal symptoms and maximal duration as approximately 5 years. The WHI finding of net harm was due largely to the absence of beneficial effects on coronary heart disease incidence rates. Published analyses of WHI data by age or time since menopause find that excess coronary heart disease risk with menopausal hormone treatment is confined to more remotely menopausal or older women, with younger women showing nonsignificant trends toward benefit (the "timing hypothesis"). Moreover, a recently published reexamination of data from the WHI Estrogen plus Progestin trial suggests that reduced coronary heart disease risk may appear only after 5 to 6 years of treatment. Consistent with this finding, risk ratios for coronary heart disease were calculated as 1.08 (95% confidence interval, 0.86-1.36) in years 1 to 6 and as 0.46 (confidence interval, 0.28-0.78) in years 7 to 8+ in the WHI Estrogen Alone trial. Previous studies also support the beneficial effects of menopausal hormone treatment after prolonged exposure. Thus, current analyses do not support a generalized recommendation for short duration of menopausal hormone treatment. Rather, they suggest that current Food and Drug Administration practice guidelines should be reconsidered to allow individualized care based on risk:benefit considerations. New research is urgently needed evaluating influences of timing, duration, dose, route of administration, and agents on menopausal hormone treatment-related risks and benefits to better understand how to optimize recommendations for individual patients.

Cognitive benefits of hormone therapy: cardiovascular factors and healthy-user bias

OBJECTIVE

The Women's Health Initiative (WHI) study and its ancillary Memory Study (WHIMS) revealed increased rates of cardiovascular risk, cognitive decline and dementia with opposed conjugated equine estrogens (CEE). As a result, previously accepted observational data suggesting cardiovascular and cognitive benefits and reduced risk for dementia with hormone therapy (HT) were largely attributed to 'healthy-user' bias. The present observational, community-based, case-controlled study examined the 'healthy-user' bias theory by comparing cognitive task performance in two groups of postmenopausal women, who were either HT users or non-users.

DESIGN

Participants were 213 non-demented, postmenopausal women residing in the community and in assisted-living facilities who completed a self-report health questionnaire and underwent a 1-h cognitive test battery. To study the independent contribution of variables in the prediction of cognitive performance, we employed a series of hierarchical regression models adding terms in three stages. The first stage included only HT, the second stage added demographics, and the last stage added alcohol, depression and a cardiovascular risk factor (CVRF) composite derived from a confirmatory factor analysis. The CVRF composite consisted of: stroke, diabetes, hypertension, and hypercholesterolemia.

RESULTS

Although independent samples t-tests revealed no statistically significant differences in the CVRF composite and its individual components between the two groups, HT users tended to possess fewer CVRF than non-users. Conversely, HT users were younger and more educated than non-users. HT users outperformed non-users on 7/9 cognitive variables. The full regression model controlling for CVRF, demographic variables, and mood showed HT users outperformed non-users on measures of verbal memory and abstract reasoning.

CONCLUSIONS

While there is some evidence HT users possess fewer preexisting CVRF than non-users, the observed positive association between HT and cognition is not completely explained by this trend.

Low levels of adiponectin predict worsening of arterial morphology and function

Adipocytokines are under investigation as mediators of cardiovascular risk. In 142 non-diabetic postmenopausal women, we investigated whether plasma levels of adiponectin and leptin are associated with changes in carotid intima-media thickness (IMT) and distensibility as assessed by high-resolution ultrasound. Adiponectin but not leptin correlated weakly with baseline measures of IMT and distensibility. After 12 months, carotid IMT showed a significant progression [0.023 mm (95% CI, 0.014-0.031 mm)] whereas stiffness was unaltered. A threshold was identified for the relation of adiponectin with both progression of IMT and stiffness. Age-adjusted adiponectin levels in the lowest quartile versus second to fourth quartile were related to progression of IMT (odds ratio, 2.99; 95% CI, 1.81-5.09) and stiffness (odds ratio, 1.71; 95% CI, 1.19-4.07). Adjustment for possible confounding factors and intermediates weakened this association only to a minor degree. No such associations were observed for leptin. We conclude that low levels of adiponectin are associated with adverse changes in morphology and function of central arteries over time independently of other cardiovascular risk factors in postmenopausal non-diabetic women.

Is the estrogen controversy over? Deconstructing the Women's Health Initiative study: a critical evaluation of the evidence

The Women's Health Initiative (WHI) hormone trials have been widely interpreted as demonstrating that combined menopausal hormone therapy (HT) fails to protect against-and may increase-cardiovascular disease (CVD), stroke, and dementia in menopausal women, regardless of whether initiated early in the menopause or later. This conclusion does not agree with results of large epidemiological studies showing protection by HT and by estrogen replacement alone (ET) against CVD and dementia. One possible reason for this inconsistency is that the epidemiologic data are confounded by "healthy user bias." Another possible explanation is that most women in the observational studies initiated ET or HT at or near the menopausal transition, at which point there is little or no arterial injury, whereas, in the WHI studies, older women, averaging approximately 12 years postmenopausal, many of whom would have had significant asymptomatic atherosclerosis, were treated. Substantial data demonstrate atheropreventive effects of estrogen before vascular damage occurs, whereas adverse effects of oral estrogen on thrombosis and inflammation may predominate once complex atheromas are present. Similarly, the excess of dementia observed in older WHI women treated with oral conjugated estrogen could be due to cerebral thromboses (multi-infarct dementia). Given the uncertain relevance of the WHI (and other published randomized clinical trials) to initiation of HT in perimenopausal women, and its subsequent continuation for atheroprevention, new trials will be needed to resolve whether early intervention with estrogen may prevent CVD and/or dementia. The Kronos Early Estrogen Prevention Study (KEEPS), which began in mid-2005, is a randomized, controlled multicenter trial of HT in recently menopausal women. It will examine surrogate end points as well as risk factors for atherosclerosis.

Hormone replacement therapy and cognitive performance in postmenopausal women—a review by cognitive domain

Laboratory, animal and neuroimaging evidences suggest that hormone replacement therapy (HRT) may be beneficial to human cognition. This systematic review includes 26 studies on the association between HRT and cognition and 17 studies on HRT and risk of dementia. It was hypothesised that HRT would have a positive association with cognitive speed and verbal memory and possibly visual memory but not with executive functioning, and would be associated with a decreased risk of dementia. Evidence for HRT's neuroenhancing and neuroprotective properties was also evaluated. There was significant statistical and clinical heterogeneity among studies precluding meta-analysis. Results showed no consistent relationship between HRT and performance in any cognitive domain. Cross-sectional studies tended to report more positive results than longitudinal studies and randomised-controlled trials, particularly in the areas of verbal memory and executive functioning. HRT was associated with decreased risk of dementia in observational studies, but with increased risk in one randomised-controlled trial. Cognitive improvement or maintenance are not secondary benefits of HRT.

Is the WHI relevant to HRT started in the perimenopause?

The Women's Health Initiative (WHI) hormone replacement therapy (HRT) estrogen plus progestin (E+P) and estrogen-only arms are part of a large NIH-sponsored randomized controlled trial (RCT). Both arms were terminated prematurely after 5 and 8 yr, respectively. The E+P arm showed non-statistically significant increased incidences of cardiovascular events and breast cancer, whereas the E-only arm did not. Both arms showed an increased rate of thromboembolic events and stroke. Both arms showed protection against fractures and with protection against colon cancer only in the E+P arm. These results have been widely generalized as indicating a negative risk/benefit ratio for HRT in menopausal women. The WHI results are at odds with results of large epidemiological studies that showed protection against cardiovascular disease. Although the latter data are, in part, confounded by a "healthy user bias," much of the inconsistency may be explained by the fact that women in the latter studies initiated HRT at the menopausal transition, whereas the WHI trial was conducted in older women (mean age 63.3), who were, on average, approx 12 yr postmenopausal. In addition, older trials included women on either unopposed estrogen therapy (ERT) or cyclic HRT regimens. Whatever other forces may have been at work, observational and experimental evidence supports the conclusion that estrogen's atheropreventive effects predominate early, in the absence of vulnerable plaque to be ruptured or thrombotic episodes propagated by narrowed lumens and intravascular turbulence. On the contrary, age-related adverse effects of HRT may prevail once complex atheromas and luminal narrowing/irregularity are established. It is known that prevalence of subclinical "at-risk" atherosclerotic lesions increases in women during the first 5-10 yr after menopause. Furthermore, animal and clinical evidence supports the use of lower doses of estrogen than were employed in the WHI in older/longer postmenopausal women.

Effects of low-dose oral and transdermal estrogen replacement therapy on hemostatic factors in healthy postmenopausal women: A randomized placebo-controlled study

OBJECTIVE

This study was undertaken to investigate the effect of transdermal and oral estrogen replacement therapy in healthy postmenopausal women on markers of coagulation and fibrinolysis associated with coronary artery disease.

STUDY DESIGN

In a randomized, placebo-controlled, double-blind study, healthy hysterectomized postmenopausal women received daily either placebo (n=49), transdermal 17beta-estradiol (E(2)) 50 microg (tE(2) group, n=33), oral E(2) 1 mg (oE(2) group, n=37), or oral E(2) 1 mg combined with gestodene 25 microg (oE(2)+G group, n=33) for thirteen 28-day treatment cycles. Hemostatic variables were measured in blood samples collected at baseline and in cycles 4 and 13.

RESULTS

No significant changes versus baseline and placebo were found in the tE(2) group, except for plasminogen activator inhibitor type-1 (PAI-1) in cycle 13 (-32.4%, P=.01). In the oE(2) group, significant percentage changes from baseline versus placebo in cycle 13 were found in fibrinogen, -5.4% (P<.05); factor VII, -7.3% (P<.05); thrombin-antithrombin III complexes, -13.3% (P<.05); tissue-type plasminogen activator (t-PA), -17.3% (P<.001); and PAI-1, -54.3% (P<.001). In the oE(2)+G group, respective changes were factor VII, -17.6% (P<.001); t-PA, -14.5% (P=.01); PAI-1, -36.4% (P<.01); and D-dimer, +21.8% (P<.05). No significant changes were observed in prothrombin fragment 1+2 and plasmin-alpha(2)-antiplasmin complexes.

CONCLUSION

Low-dose oral estradiol therapy was associated with an increase in fibrinolysis and small decreases in procoagulant variables. Transdermal therapy had minor effects.