Expert Commentary
Does the discontinuation of menopausal hormone therapy affect a woman’s cardiovascular risk?
No.
In this Update, I discuss important new study results regarding the cardiovascular safety of hormone therapy (HT) in early menopausal women. In addition, I review survey data that reveal a huge number of US women are using compounded HT preparations, which have unproven efficacy and safety.
Earlier initiation is better: ELITE trial provides strong support for the estrogen timing hypothesis
Hodis HN, Mack WJ, Henderson VW, et al; for the ELITE Research Group. Vascular effects of early versus late postmenopausal treatment with estradiol. N Engl J Med. 2016;374(13):1221-1231.
Keaney JF, Solomon G. Postmenopausal hormone therapy and atherosclerosis--time is of the essence [editorial]. N Engl J Med. 2016;374(13):1279-1280.
A substantial amount of published data, including from the Women's Health Initiative (WHI), supports the timing hypothesis, which proposes that HT slows the progression of atherosclerosis among recently menopausal women but has a neutral or adverse effect among women who are a decade or more past menopause onset.1 To directly test this hypothesis, Hodis and colleagues randomly assigned healthy postmenopausal women (<6 years or ≥10 years past menopause) without cardiovascular disease (CVD) to oral estradiol 1 mg or placebo. Women with a uterus also were randomly assigned to receive either vaginal progesterone gel or placebo gel. The primary outcome was the rate of change in carotid artery intima-media thickness (CIMT), which was assessed at baseline and each 6 months of the study. (An earlier report had noted that baseline CIMT correlated well with CVD risk factors.2) Coronary artery atherosclerosis, a secondary outcome, was assessed at study completion using computed tomography (CT).
Details of the study
Among the 643 participants in the Early versus Late Intervention Trial with Estradiol (ELITE), the median years since menopause and the median age at enrollment were 3.5 and 55.4, respectively, in the early postmenopause group and 14.3 and 63.6, respectively, in the late postmenopause group.
Among the younger women, after a median of 5 years of study medications, the estradiol group had less progression of CIMT than the placebo group (P = .008). By contrast, in the older group, rates of CIMT progression were similar in the HT and placebo groups (P = .29). The relationship between estrogen and CIMT progression differed significantly between the younger and older groups (P = .007). Use of progesterone did not change these trends. Coronary artery CT parameters did not differ significantly between the placebo and HT groups in the age group or in the time-since-menopause group.
What this evidence means for practice
In an editorial accompanying the published results of the ELITE trial, Keaney and Solomon concluded that, although estrogen had a favorable effect on atherosclerosis in early menopause, it would be premature to recommend HT for prevention of cardiovascular events. I agree with them, but I also would like to note that the use of HT for the treatment of menopausal symptoms has plummeted since the initial WHI findings in 2002, with infrequent HT use even among symptomatic women in early menopause.3 (And I refer you to the special inset featuring JoAnn E. Manson, MD, DrPH) The takeaway message is that this important new clinical trial provides additional reassurance regarding the cardiovascular safety of HT when initiated by recently menopausal women to treat bothersome vasomotor symptoms. This message represents welcome news for women with bothersome menopausal symptoms considering use of HT.
A word about the vaginal progesterone gel used in the ELITE trial in relation to clinical practice: Given the need for vaginal placement of progesterone gel, potential messiness, and high cost, few clinicians may prescribe this formulation, and few women probably would choose to use it. As an alternative, micronized progesterone 100-mg capsules are less expensive and well accepted by most patients. These capsules are formulated with peanut oil. Because they may cause women to feel drowsy, the capsules should be taken at bedtime. In women with an intact uterus who are taking oral estradiol 1-mg tablets, one appropriate progestogen regimen for endometrial suppression is a 100-mg micronized progesterone capsule each night, continuously.
WHI, ELITE and the timing hypothesis:
New evidence on HT in early menopause is reassuring
Q&A with JoAnn E. Manson, MD, DrPH
In this interview, Dr. JoAnn Manson discusses the reassuring results of recent hormone therapy (HT) trials in early versus later postmenopausal women, examines these outcomes in the context of the Women's Health Initiative (WHI) trial and ELITE trial, and debunks an enduring common misconception about the WHI.
Q You have said for several years that there has been a misconception about the WHI trial. What is that misconception, and what has been its impact on clinicians, women, and the use of HT?
A The WHI HT trial has been largely misunderstood. It was designed to address the balance of benefits and risks of long-term HT for the prevention of chronic disease in postmenopausal women across a broad range of ages (average age 63).1,2 It was not intended to evaluate the clinical role of HT for managing menopausal symptoms in young and early menopausal women.3 Overall, the WHI study findings have been inappropriately extrapolated to women in their 40s and early 50s who report distressing hot flashes, night sweats, and other menopausal symptoms, and they are often used as a reason to deny therapy when in fact many of these women would be appropriate candidates for HT.
There is increasing evidence that younger women in early menopause who are taking HT have a lower risk of adverse outcomes and lower absolute risks of disease than older women.2,3 In younger, early menopausal women with bothersome hot flashes, night sweats, or other menopausal symptoms and who have no contraindications to HT, the benefits of treatment are likely to outweigh the risks, and these patients derive quality-of-life benefits from treatment.
Q How do the results of the recent ELITE (Early versus Late Intervention Trial with Estradiol) trial build on cardiovascular safety, in particular, of HT and when HT is optimally initiated?
A The ELITE trial directly tested the "timing hypothesis" and the role of HT in slowing the progression of atherosclerosis in early menopause (defined as within 6 years of menopause onset) compared with the effect in women in later menopause (defined as at least 10 yearspast menopause).4 The investigators used carotid artery intima-media thickness (CIMT) as a surrogate end point. In this trial, 643 women were randomly assigned according to whether they were in early or later menopause to receive either placebo or estradiol 1 mg daily; women with a uterus also received progesterone 45 mg as a 4% vaginal gel or matching placebo gel. The median duration of intervention was 5 years.
The ELITE study results provide support for the "critical window hypothesis" in that the estradiol-treated younger women closer to onset of menopause had slowing of atherosclerosis compared with the placebo group, while the older women more distant from menopause did not have slowing of atherosclerosis with estradiol.
The ELITE trial was not large enough, however, to assess clinical end points--rates of heart attack, stroke, or other cardiovascular events. So it remains unclear whether the findings for the surrogate end point of CIMT would translate into a reduced risk of clinical events in the younger women. Nevertheless, ELITE does provide more reassurance about the use of HT in early menopause and supports the possibility that the overall results of the WHI among women enrolled at an average age of 63 years may not apply directly to younger women in early menopause.
Q What impact on clinical practice do you anticipate as a result of the ELITE trial results?
A The findings provide further support for the timing hypothesis and offer additional reassurance regarding the safety of HT in early menopause for management of menopausal symptoms. However, the trial does not provide conclusive evidence to support recommendations to use HT for the express purpose of preventing cardiovascular disease (CVD), even if HT is started in early menopause. Using a surrogate end point for atherosclerosis (CIMT) is not the same as looking at clinical events. There are many biologic pathways for heart attacks, strokes, and other cardiovascular events. In addition to atherosclerosis, for example, there is thrombosis, clotting, thrombo-occlusion within a blood vessel, and plaque rupture. Again, we do not know whether the CIMT-based results would translate directly into a reduction in clinical heart attacks and stroke.
The main takeaway point from the ELITE trial results is further reassurance for use of HT for management of menopausal symptoms in early menopause, but not for long-term chronic disease prevention at any age.
Q Another recent study, published in the Journal of Clinical Endocrinology and Metabolism, addresses HT and the timing hypothesis but in this instance relating to glucose tolerance.5 What did these study authors find?
A This study by Pereira and colleagues is very interesting and suggests that the window of opportunity for initiating estrogen therapy may apply not only to coronary events but also to glucose tolerance, insulin sensitivity, and diabetes risk.5
The authors investigated the effects of short-term high-dose transdermal estradiol on the insulin-mediated glucose disposal rate (GDR), which is a measure of insulin-stimulated glucose uptake. Participants in this randomized, crossover, placebo-controlled study included 22 women who were in early menopause (6 years or less since final menses) and 24 women who were in later menopause (10 years or longer since final menses). All of the women were naïve to hormone therapy, and baseline GDR did not differ between groups. After 1 week of treatment with transdermal estradiol (a high dose of 150 μg) or placebo, the participants' GDR was measured via a hyperinsulinemic-euglycemic clamp.
The investigators found that in the younger women, estradiol had a favorable effect on insulin sensitivity and GDR, whereas in the older women, there was no evidence of a favorable effect and, in fact, there was a signal for risk and more adverse findings in this group.
Several studies in the WHI also looked at glucose tolerance and at the risk of being diagnosed with diabetes. While the results of the WHI estrogen-alone trial revealed a reduction in diabetes and favorable effects across age groups, in the WHI estrogen-plus-progestin trial we did see a signal that the results for diabetes may have been more favorable in the younger than in the older women, somewhat consistent with the findings of Pereira and colleagues.2,5
Overall this issue requires more research, but the Pereira study provides further support for the possibility that estrogen's metabolic effects may vary by age and time since menopause, and there is evidence that the estrogen receptors may be more functional and more sensitive in early rather than later menopause. These findings are very interesting and consistent with the overall hypothesis about the importance of age and time since menopause in relation to estrogen action. Again, they offer further support for use of HT for managing bothersome menopausal symptoms in early menopause, but they should not be interpreted as endorsing the use of HT to prevent either diabetes or CVD, due to the potential for other risks.
Q Where would you like to see future research conducted regarding the timing hypothesis?
A I would like to see more research on the role of oral versus transdermal estrogen in relation to insulin sensitivity, diabetes risk, and CVD risk, and more research on the role of estrogen dose, different types of progestogens, and the benefits and risks of novel formulations, including selective estrogen receptor modulators and tissue selective estrogen complexes.
Dr. Manson is Professor of Medicine and the Michael and Lee Bell Professor of Women's Health at Harvard Medical School and Chief of the Division of Preventive Medicine at Brigham and Women's Hospital, Boston, Massachusetts. She is a past President of the North American Menopause Society (NAMS) and a NAMS Certified Menopause Practitioner.
The author reports no financial relationships relevant to this article.
References
- Rossouw JE, Anderson GL, Prentice RL, et al; Writing Group for the Women's Health Initiative Investigators. Risks and benefits of estrogen plus progestin in healthy postmenopausal women: principal results from the Women's Health Initiative randomized controlled trial. JAMA. 2002;288(3):321-333.
- Manson JE, Chlebowski RT, Stefanick ML, et al. Menopausal hormone therapy and health outcomes during the intervention and extended poststopping phases of the Women's Health Initiative randomized trials. JAMA. 2013(13);310:1353-1368.
- Manson JE, Kaunitz AM. Menopause management-- getting clinical care back on track. N Engl J Med. 2016;374(19):803-806.
- Hodis HN, Mack WJ, Henderson VW, et al; ELITE Research Group. Vascular effects of early versus late postmenopausal treatment with estradiol. N Engl J Med. 2016;374(13):1221-1231.
- Pereira RI, Casey BA, Swibas TA, Erickson CB, Wolfe P, Van Pelt RE. Timing of estradiol treatment after menopause may determine benefit or harm to insulin action. J Clin Endocrinol Metab. 2015;100(12):4456-4462.
