Endometrial effects of lower doses of conjugated equine estrogens and medroxyprogesterone acetate

Hormone Therapy in Menopause: Concepts, Controversies, and Approach to Treatment

Hormone therapy (HT) is an effective treatment for menopausal symptoms, including vasomotor symptoms and genitourinary syndrome of menopause. Randomized trials also demonstrate positive effects on bone health, and age-stratified analyses indicate more favorable effects on coronary heart disease and all-cause mortality in younger women (close proximity to menopause) than in women more than a decade past menopause. In the absence of contraindications or other major comorbidities, recently menopausal women with moderate or severe symptoms are appropriate candidates for HT. The Women's Health Initiative (WHI) hormone therapy trials-estrogen and progestin trial and the estrogen-alone trial-clarified the benefits and risks of HT, including how the results differed by age. A key lesson from the WHI trials, which was unfortunately lost in the posttrial cacophony, was that the risk:benefit ratio and safety profile of HT differed markedly by clinical characteristics of the participants, especially age, time since menopause, and comorbidity status. In the present review of the WHI and other recent HT trials, we aim to provide readers with an improved understanding of the importance of the timing of HT initiation, type and route of administration, and of patient-specific considerations that should be weighed when prescribing HT.

Estrogen therapy for osteoporosis in the modern era

Menopause predisposes women to osteoporosis due to declining estrogen levels. This results in a decrease in bone mineral density (BMD) and an increase in fractures. Osteoporotic fractures lead to substantial morbidity and mortality, and are considered one of the largest public health priorities by the World Health Organization (WHO). It is therefore essential for menopausal women to receive appropriate guidance for the prevention and management of osteoporosis. The Women's Health Initiative (WHI) randomized controlled trial first proved hormonal therapy (HT) reduces the incidence of all osteoporosis-related fractures in postmenopausal women. However, the study concluded that the adverse effects outweighed the potential benefits on bone, leading to a significant decrease in HT use for menopausal symptoms. Additionally, HT was not used as first-line therapy for osteoporosis and fractures. Subsequent studies have challenged these initial conclusions and have shown significant efficacy of HT in various doses, durations, regimens, and routes of administration. These studies support that HT improves BMD and reduces fracture risk in women with and without osteoporosis. Furthermore, the studies suggest that low-dose and transdermal HT are less likely associated with the adverse effects of breast cancer, endometrial hyperplasia, coronary artery disease (CAD), and venous thromboembolism (VTE) previously observed in standard-dose oral HT regimens. Given the need for estrogen in menopausal women and evidence supporting the cost effectiveness, safety, and efficacy of HT, we propose that HT should be considered for the primary prevention and treatment of osteoporosis in appropriate candidates. HT should be individualized and the once "lowest dose for shortest period of time" concept should no longer be used. This review will focus on the prior and current studies for various HT formulations used for the prevention and treatment of osteoporosis, exploring the safety profile of low-dose and transdermal HT that have been shown to be safer than oral standard-dose HT.

Pharmacokinetics of the first combination 17β-estradiol/progesterone capsule in clinical development for menopausal hormone therapy

Objective:

This study aims to compare the pharmacokinetics and oral bioavailability of a capsule combining 17β-estradiol and progesterone in a non–peanut oil–containing formulation with those of widely used and approved separate formulations of estradiol and progesterone coadministered to healthy postmenopausal women.

Methods:

This was an open-label, balanced, randomized, single-dose, two-treatment, three-period, three-sequence, cross-over, partial-replicate, reference-scaled study. Postmenopausal women (aged 40-65 y) were randomly assigned to one of three dosing sequences of test and reference products (TRR, RTR, or RRT, where T is the test drug and R is the coadministered reference product), with each of the three periods separated by a 14-day washout. The primary pharmacokinetic endpoints were C_max, AUC_(0-t), and AUC_(0-inf) for the test and reference products, assessed for bioequivalence using the scaled average bioequivalence or unscaled average bioequivalence method. Safety was assessed by clinical observation, participant-reported adverse events, and laboratory data, including blood levels of hormones.

Results:

Sixty-six women were randomly assigned, and 62 women (94.0%) completed all three study periods. All AUC and C_max parameters met bioequivalence criteria for all analytes (estradiol, progesterone, and estrone), except C_max for total estrone. The extent of estradiol and progesterone absorption was similar between the test product and the reference products. Four adverse events—all considered mild and unrelated to the study drugs—were reported.

Conclusions:

The combination 17β-estradiol/progesterone product demonstrates bioavailability similar to those of the respective reference products of estradiol and progesterone. If regulatory approval is obtained, this new hormone therapy would be the first treatment of menopause symptoms to combine progesterone with 17β-estradiol in an oral formulation.

Endometrial safety of ospemifene: results of the phase 2/3 clinical development program

OBJECTIVE

This study aims to assess the endometrial safety of ospemifene based on phase 2/3 clinical trials of postmenopausal women with up to 52 weeks of exposure to ospemifene 60 mg/day versus placebo.

METHODS

Endometrial safety was evaluated in a development program of six randomized, double-blind, placebo-controlled, parallel-group studies of postmenopausal women aged between 40 and 80 years who had vulvar and vaginal atrophy. Participants were randomized 1:1 to ospemifene 60 mg/day or placebo in one 6-week trial and three 12-week trials; one of the 12-week trials had a 40-week extension study. In a separate 52-week trial, women were randomized 6:1 to ospemifene 60 mg/day or placebo. Endometrial safety was assessed by endometrial histology (biopsy), transvaginal ultrasound, and gynecologic examination.

RESULTS

In these trials, 1,242 women who received ospemifene 60 mg/day and 924 women who received placebo were evaluable for safety. Endometrial hyperplasia occurred in less than 1% of women treated with ospemifene; no endometrial cancer was reported. The mean (SD) increase in endometrial thickness among women treated with ospemifene was 0.51 (1.54) mm at 12 weeks, 0.56 (1.61) mm at 6 months, and 0.81 (1.54) mm at 12 months. Women who received placebo had a mean (SD) increase of 0.07 (1.23) mm at 12 months.

CONCLUSIONS

These clinical trial data indicate that up to 52 weeks of treatment with oral ospemifene 60 mg/day was safe for the endometrium. There was no increase in the incidence of endometrial cancer or hyperplasia among postmenopausal women treated with ospemifene compared with placebo.

Abnormal bleeding during menopause hormone therapy: insights for clinical management

OBJECTIVE

Our objective was to review the involved mechanisms and propose actions for controlling/treating abnormal uterine bleeding during climacteric hormone therapy.

METHODS

A systemic search of the databases SciELO, MEDLINE, and Pubmed was performed for identifying relevant publications on normal endometrial bleeding, abnormal uterine bleeding, and hormone therapy bleeding.

RESULTS

Before starting hormone therapy, it is essential to exclude any abnormal organic condition, identify women at higher risk for bleeding, and adapt the regimen to suit eachwoman's characteristics. Abnormal bleeding with progesterone/progestogen only, combined sequential, or combined continuous regimens may be corrected by changing the progestogen, adjusting the progestogen or estrogen/progestogen doses, or even switching the initial regimen to other formulation.

CONCLUSION

To diminish the occurrence of abnormal bleeding during hormone therapy (HT), it is important to tailor the regimen to the needs of individual women and identify those with higher risk of bleeding. The use of new agents as adjuvant therapies for decreasing abnormal bleeding in women on HT awaits future studies.

Hormone therapy in postmenopausal women and risk of endometrial hyperplasia

BACKGROUND

Reduced circulating estrogen levels around the time of the menopause can induce unacceptable symptoms that affect the health and well-being of women. Hormone therapy (both unopposed estrogen and estrogen/progestogen combinations) is an effective treatment for these symptoms, but is associated with risk of harms. Guidelines recommend that hormone therapy be given at the lowest effective dose and treatment should be reviewed regularly. The aim of this review is to identify the minimum dose(s) of progestogen required to be added to estrogen so that the rate of endometrial hyperplasia is not increased compared to placebo.

OBJECTIVES

The objective of this review is to assess which hormone therapy regimens provide effective protection against the development of endometrial hyperplasia or carcinoma.

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (searched January 2012), The Cochrane Library (Issue 1, 2012), MEDLINE (1966 to January 2012), EMBASE (1980 to January 2012), Current Contents (1993 to May 2008), Biological Abstracts (1969 to 2008), Social Sciences Index (1980 to May 2008), PsycINFO (1972 to January 2012) and CINAHL (1982 to May 2008). Attempts were made to identify trials from citation lists of reviews and studies retrieved, and drug companies were contacted for unpublished data.

SELECTION CRITERIA

Randomised comparisons of unopposed estrogen therapy, combined continuous estrogen-progestogen therapy, sequential estrogen-progestogen therapy with each other or placebo, administered over a minimum period of 12 months. Incidence of endometrial hyperplasia/carcinoma assessed by a biopsy at the end of treatment was a required outcome. Data on adherence to therapy, rates of additional interventions, and withdrawals owing to adverse events were also extracted.

DATA COLLECTION AND ANALYSIS

In this update, 46 studies were included. Odds ratios (ORs) were calculated for dichotomous outcomes. The small numbers of studies in each comparison and the clinical heterogeneity precluded meta-analysis for many outcomes.

MAIN RESULTS

Unopposed estrogen is associated with increased risk of endometrial hyperplasia at all doses, and durations of therapy between one and three years. For women with a uterus the risk of endometrial hyperplasia with hormone therapy comprising low-dose estrogen continuously combined with a minimum of 1 mg norethisterone acetate (NETA) or 1.5 mg medroxyprogesterone acetate (MPA) is not significantly different from placebo at two years (1 mg NETA: OR 0.04; 95% confidence interval (CI) 0 to 2.8; 1.5 mg MPA: no hyperplasia events).

AUTHORS' CONCLUSIONS

Hormone therapy for postmenopausal women with an intact uterus should comprise both estrogen and progestogen to reduce the risk of endometrial hyperplasia.

Tissue-selective agents: selective estrogen receptor modulators and the tissue-selective estrogen complex

Menopause has been associated with vasomotor symptoms, vulvar-vaginal atrophy and osteoporosis. One of the goals in exploring the potential of selective estrogen receptor modulators (SERMs) was to determine if they could prevent fractures, reduce menopausal symptoms and treat vaginal atrophy, while being neutral or protective on the uterus, breast and cardiovascular system. However, no SERM to date has achieved this goal. More recently, the idea of pairing a SERM with estrogen(s), known as a tissue-selective estrogen complex (TSEC), has been studied in postmenopausal women. A TSEC combines the complementary tissue-selective activities of a SERM and estrogen(s), in an attempt to gain the benefits of each with better overall tolerability. The Selective estrogen Menopause And Response to Therapy (SMART) trials were multicentre, randomized, double-blind, placebo- and active-controlled phase 3 studies evaluating the safety and efficacy of the SERM, bazedoxifene (BZA) paired with conjugated estrogens (CEs) in healthy postmenopausal women. In the first SMART trial, BZA/CE protected the endometrium from estrogenic stimulation, relieved hot flushes and maintained bone mass, with rates of amenorrhea, breast pain and overall adverse events similar to those with placebo in more than 3400 women over two years. BZA 20 mg was the lowest effective dose of BZA in BZA/CE to protect the endometrium and maintain bone mass when paired with CE 0.625 mg and CE 0.45 mg. In SMART-2, these BZA/CE doses significantly reduced the frequency and severity of hot flushes over 12 weeks. Collectively, these data support the TSEC containing BZA/CE as a new paradigm for treating menopausal symptoms and preventing osteoporosis while protecting the endometrium from unopposed estrogenic stimulation.

A novel regimen of combination transdermal estrogen and intermittent vaginally administered progesterone for relief of menopausal symptoms

OBJECTIVES

To determine the safety and efficacy of a novel regimen of transdermal estrogen and vaginally administered progesterone for treatment of menopausal symptoms.

STUDY METHODS

A retrospective chart review was conducted of menopausal patients aged 46-65, using an oestradiol patch and vaginally administered prometrium for at least 1 year. Available transvaginal ultrasound (TVUS) measurements of endometrial thickness and endometrial biopsy results after at least 1 year of treatment were collated. Symptom relief, bleeding and side effects were reviewed.

RESULTS

Forty-one patients were identified, using an estrogen patch ranging from 25 to 100 μg twice weekly and vaginal prometrium either continuously 3-5 days weekly (36 patients), or sequentially 12 days/month (5 patients). Seventeen patients were lost to follow-up or discontinued therapy within 1 year. Only 23.5% (4/17 patients) of patients who had a TVUS after 1 year (or sooner if bleeding occurred) had a thickened endometrial lining on ultrasound (>5 mm), and all of these had normal endometrial biopsies. By 1 year of follow-up, 91.7% of patients were amenorrhoeic. All patients had relief of menopausal symptoms.

CONCLUSIONS

Vaginal administration of progesterone as part of combined estrogen plus progestin therapy has the potential for decreasing side effects while maintaining endometrial safety and amenorrhoea. Larger prospective trials are warranted.

The endometrium--from estrogens alone to TSECs

This article reviews publications dating back more than a century describing investigations of the endometrium, including those examining the relationship between endometrial hyperplasia and carcinoma, the influence of estrogens on the endometrium, and strategies for protecting the endometrium from unopposed estrogen stimulation. Endometrial hyperplasia and carcinoma studies date from before 1900. The influence of endogenous estrogens on the endometrium became evident with observations of endometrial hyperplasia and/or carcinoma in women with estrogen-secreting tumors or polycystic ovarian disease. Later, observational studies and randomized, controlled trials suggested a relationship between unopposed estrogens and endometrial cancer and hyperplasia. The first, and to date only, effective clinical strategy for protecting the endometrium from unopposed estrogen stimulation has been the use of progestins. A new approach for endometrial protection in menopausal therapy is the pairing of a selective estrogen receptor modulator (SERM) with estrogen(s), also known as a tissue selective estrogen complex (TSEC). Effective protection of the endometrium as well as treatment of menopausal symptoms and prevention of osteoporosis would be key elements for a clinically useful TSEC.

Endometrial effects of a tissue selective estrogen complex containing bazedoxifene/conjugated estrogens as a menopausal therapy

OBJECTIVE

To evaluate the endometrial safety of a tissue selective estrogen complex (TSEC; pairing of a selective estrogen receptor modulator [SERM] with estrogens) composed of bazedoxifene/conjugated estrogens (BZA/CE) in postmenopausal women.

DESIGN

Randomized, double-blind, multicenter, placebo- and active-controlled, phase 3 study (Selective estrogen Menopause And Response to Therapy [SMART]-1).

SETTING

Outpatient clinical.

PATIENT(S)

Healthy, postmenopausal women (n = 3,397) age 40-75 with an intact uterus.

INTERVENTION(S)

Single tablets of BZA (10, 20, or 40 mg) combined with CE (0.625 or 0.45 mg); raloxifene (60 mg); or placebo daily for 2 years.

MAIN OUTCOME MEASURE(S)

Incidence of endometrial hyperplasia at 12 months in the efficacy evaluable population.

RESULT(S)

Treatment with BZA (20 or 40 mg)/CE (0.625 or 0.45 mg) was associated with low rates (<1%) of endometrial hyperplasia that were not significantly different from those reported with placebo over 24 months. Endometrial thickness with BZA (20 or 40 mg)/CE (0.625 or 0.45 mg) was not significantly different from that with placebo.

CONCLUSION(S)

When combined with CE (0.625 mg or 0.45 mg), BZA (20 mg) was the lowest effective dose that prevented endometrial hyperplasia over 2 years of study, creating the possibility for a new, progestin-free menopausal therapy.

Hormone therapy in postmenopausal women and risk of endometrial hyperplasia

BACKGROUND

Declining circulating estrogen levels around the time of the menopause can induce unacceptable symptoms that affect the health and well being of women. Hormone therapy (both unopposed estrogen and estrogen/progestogen combinations) is an effective treatment for these symptoms, but is associated with risk of harms. Guidelines recommend that hormone therapy be given at the lowest effective dose and treatment should be reviewed regularly. The aim of this review is to identify the minimum dose(s) of progestogen required to be added to estrogen so that the rate of endometrial hyperplasia is not increased compared to placebo.

OBJECTIVES

The objective of this review is to assess which hormone therapy regimens provide effective protection against the development of endometrial hyperplasia and/or carcinoma.

SEARCH STRATEGY

We searched the Cochrane Menstrual Disorders and Subfertility Group trials register (searched January 2008), The Cochrane Library (Issue 1, 2008), MEDLINE (1966 to May 2008), EMBASE (1980 to May 2008), Current Contents (1993 to May 2008), Biological Abstracts (1969 to 2008), Social Sciences Index (1980 to May 2008), PsycINFO (1972 to May 2008) and CINAHL (1982 to May 2008). Attempts were made to identify trials from citation lists of reviews and studies retrieved, and drug companies were contacted for unpublished data.

SELECTION CRITERIA

Randomised comparisons of unopposed estrogen therapy, combined continuous estrogen-progestogen therapy and/or sequential estrogen-progestogen therapy with each other or placebo, administered over a minimum period of twelve months. Incidence of endometrial hyperplasia/carcinoma assessed by a biopsy at the end of treatment was a required outcome. Data on adherence to therapy, rates of additional interventions, and withdrawals due to adverse events were also extracted.

DATA COLLECTION AND ANALYSIS

In this substantive update, forty five studies were included. Odds ratios were calculated for dichotomous outcomes. The small numbers of studies in each comparison and the clinical heterogeneity precluded meta analysis for many outcomes.

MAIN RESULTS

Unopposed estrogen is associated with increased risk of endometrial hyperplasia at all doses, and durations of therapy between one and three years. For women with a uterus the risk of endometrial hyperplasia with hormone therapy comprising low dose estrogen continuously combined with a minimum of 1 mg norethisterone acetate or 1.5 mg medroxyprogesterone acetate is not significantly different from placebo (1mg NETA: OR=0.04 (0 to 2.8); 1.5mg MPA: no hyperplasia events).

AUTHORS' CONCLUSIONS

Hormone therapy for postmenopausal women with an intact uterus should comprise both estrogen and progestogen to reduce the risk of endometrial hyperplasia.

Endometrial hyperplasia risk in relation to recent use of oral contraceptives and hormone therapy

PURPOSE

We sought to examine the relationship between recent use of oral contraceptives and hormone therapy and endometrial hyperplasia (EH) risk.

METHODS

Cases comprised women diagnosed with complex EH (n = 289) or atypical EH (n = 173) between 1985 and 2003. One age-matched control was selected for each case; excluded were women with a prior hysterectomy or diagnosis of EH or endometrial cancer. Hormone use in the 6 months prior to the date of the case's first symptoms was ascertained using a pharmacy database and medical records. Odds ratios (OR) and 95% confidence intervals (CI) were calculated.

RESULTS

Three (1.1%) cases had used oral contraceptives, compared to 16 (6.0%) controls (OR = 0.2, 95% CI: 0.0-0.6). Fifty-one (16.8%) cases had taken estrogen-only hormone therapy, in contrast to two (0.7%) controls (OR = 37.6, 95% CI: 8.8-160.0). The risk of EH among estrogen plus progestin hormone users did not differ from that of non-users (OR = 0.7, 95% CI: 0.4-1.1).

CONCLUSIONS

This study suggests that previous findings of the association of estrogen-only hormone therapy with increased risk of EH and the lack of an association between estrogen plus progestin hormone therapy and EH risk are likely to apply to both complex EH and atypical EH. Further examination of the association between oral contraceptives and EH, with greater numbers of OC users, is warranted.

Reassessing Benefits and Risks of Hormone Therapy

Recent randomized clinical trials of postmenopausal hormone therapy have informed clinical decision making and provided insights that help identify appropriate candidates for treatment. A decline in the use of hormone therapy began precipitously in 2002 with publication of data from the Women's Health Initiative. This review examines the scientific literature surrounding this major change in practice and comments on the equilibrating process now taking place. Notably, the incidence of most of the medical conditions adversely affected by hormone therapy increases with age. As a result, recently menopausal women—those most interested in using hormone therapy—are at lower absolute risk of adverse events than older women. A critical mass of data now suggests that age and time since menopause may also modify relative risks of selected outcomes with use of hormone therapy, but this warrants further study. Duration of hormone therapy use also appears to influence risk, with the occurrence of certain outcomes (such as venous thrombosis) being highest in the first 1 or 2 years of hormone therapy use and others (such as breast cancer) increasing with longer duration of hormone therapy use. The conflicting results for some outcomes from the estrogen arm and the estrogen-progestin arm of the Women's Health Initiative suggest that progestins influence risk of several diseases, particularly breast cancer. Quantifying the benefits and risks of estrogen and estrogen-progestin by age group makes it possible to discuss pros and cons of hormone therapy in a more clinically relevant manner with patients. Hormone therapy remains a viable short-term option for the management of moderate to severe vasomotor symptoms in recently menopausal women who are in generally good health. However, due to known risks, it should not be initiated or continued for the express purpose of preventing cardiovascular disease or other chronic diseases.

Rationale for low-dose systemic hormone replacement therapy and review of estradiol 0.5 mg/NETA 0.1 mg

The menopausal transition is associated with several symptoms, for which both non-pharmacological and pharmacological measures are available to provide relief. However, present knowledge indicates that the former is not highly effective, and that the latter, in terms of systemic oestrogen and progestogen-based hormone replacement therapy (HRT), although being effective (e.g. on vasomotor symptoms, bleeding control, bone mineral density, vaginal atrophy and quality of life), can be associated with some caveats. Amongst these are an increased risk for coronary heart disease, breast cancer, venous thromboembolism and stroke. In recent years, literature has indicated a dose dependency for HRT on some of the caveats, hence authorities (Food and Drug Administration, and the European Medicines Agency) and menopause societies (International Menopause Society and North American Menopause Society) now recommend that women deemed in need of HRT should receive the lowest possible dose without compromising the effect of symptom relief. Estradiol 0.5 mg/norethisterone acetate (NETA) 0.1 mg, despite being a lower dose than conventional hormones, is a compound, among a few other low-dose options, that can be used in such therapy. As a first-line oral option, it has demonstrated its effectiveness (which seems comparable to other compounds), with high tolerability and, apparently, no safety concerns, in a 6-month study. Further long-term clinical trials and observational studies are mandatory in order to capture any potential harm as well as to elucidate this compound's full potential. Following a thorough literature search using PubMed and MEDLINE from the earliest publication dates through to January 2008, including results from various types of clinical trials and statements on HRT, we review the rationale for these recommendations. We also review the effects and safety of a novel 'ultra-low-dose' oral continuous combined HRT tablet, estradiol 0.5 mg/NETA 0.1 mg.

Tibolone histology of the endometrium and breast endpoints study: design of the trial and endometrial histology at baseline in postmenopausal women

OBJECTIVE

To address the endometrial safety of tibolone.

DESIGN

The Tibolone Histology of the Endometrium and Breast Endpoints Study (THEBES) is a randomized, double-blind, parallel-group trial of tibolone compared with continuous combined conjugated equine estrogen (CEE) and medroxyprogesterone acetate (MPA).

SETTING

Multi-country, multi-center ambulatory care setting.

PATIENT(S)

A total of 5,185 subjects were screened, and biopsies were obtained from 4,446 women.

INTERVENTION(S)

Participants were randomized in a 1:1:2 ratio, to tibolone (1.25 or 2.5 mg/d) or CEE-MPA.

MAIN OUTCOME MEASURE(S)

The one-sided 95% confidence intervals for the incidence of hyperplasia or cancer were evaluated for tibolone compared with CEE-MPA.

RESULT(S)

Endometrial biopsy results at baseline: atrophic (87.29%), inactive (0.25%), proliferative (6.12%), secretory (2.86%), menstrual type (0.40%), and hyperplasia (0.18%). Only subjects with atrophic or inactive endometrium were eligible for this study, and 3% of the women at screening either had no tissue (0.18%) or had an amount of tissue that was insufficient for diagnosis (2.72%). Three thousand two hundred forty postmenopausal women with a mean (+/-SD) age of 54.4 +/- 4.4 years and a mean time since menopause of 4.5 +/- 3.6 years were randomized.

CONCLUSION(S)

The Tibolone Histology of the Endometrium and Breast Endpoints Study is a prospective, randomized clinical trial, designed to provide evidence of the endometrial safety of tibolone compared with estrogen and progestogen. Screening endometrial histology shows a low prevalence of endometrial hyperplasia (0.18%) and no carcinoma.

Body composition during treatment with conjugated estrogens with and without medroxyprogesterone acetate: analysis of the women's Health, Osteoporosis, Progestin, Estrogen (HOPE) trial

OBJECTIVE

The objective of the study was to determine the effects of several doses of conjugated estrogens (CE) and CE plus medroxyprogesterone acetate (MPA) on body composition (BC).

STUDY DESIGN

This was a randomized, double-blind, placebo-controlled substudy of the Women's Health, Osteoporosis, Progestin, Estrogen (HOPE) trial. Healthy women (n = 822, 1-4 years after menopause) were randomly assigned to receive the following treatments daily for 2 years: CE, 0.625 mg; CE, 0.625 mg, and MPA, 2.5 mg; CE, 0.45 mg; CE, 0.45 mg, and MPA, 2.5 mg; CE, 0.45 mg, and MPA, 1.5 mg; CE, 0.3 mg; CE, 0.3 mg, and MPA, 1.5 mg; or placebo. Body weight (BW) was assessed every 3-4 cycles and fat body mass (FBM), lean body mass (LBM), and percent body fat (PBF) at cycles 6, 13, 19, and 26.

RESULTS

In the placebo group, BW, FBM, and PBF increased at each visit during the study. Changes in these parameters were smaller in the active groups. These effects were independent of CE dose and the presence of MPA. Changes in LBM were small and comparable across groups.

CONCLUSION

Treatment with CE or CE and MPA for up to 2 years does not affect BC.

Care of the menopausal patient: A nurse practitioner?s view

PURPOSE

To evaluate the benefits and risks of hormone therapy (HT) and other treatment options for early postmenopausal women.

DATA SOURCES

Published clinical trials, selected peer-reviewed literature, and recent clinical practice guidelines.

CONCLUSIONS

Results of the Women's Health Initiative (WHI) studies on HT may not be directly applicable to healthy, early postmenopausal women suffering from hot flushes. HT is the most effective treatment for menopausal symptoms. The benefits of HT in relieving menopausal symptoms are likely to exceed the risks in this population.

IMPLICATIONS FOR PRACTICE

The results of the WHI reinforce the importance of individualized care based on a woman's medical history, medical needs, and desired outcomes. Nurse practitioners can help their patients put recent results into perspective. When HT is used, nurse practitioners should consider using lower doses and reevaluate the need for therapy annually.

Comparison of the effects of raloxifene and low-dose hormone replacement therapy on bone mineral density and bone turnover in the treatment of postmenopausal osteoporosis

OBJECTIVE

The aim of the present study was to compare the effects of raloxifene and low-dose hormone replacement therapy (HRT) on bone mineral density (BMD) and bone turnover markers in the treatment of postmenopausal osteoporosis.

METHODS

Forty-two postmenopausal osteoporotic women, who were randomized to receive raloxifene 60 mg or estradiol 1 mg/norethisterone acetate 0.5 mg daily for 1 year, were studied. All women received calcium 600 mg/day and vitamin D 400 IU/day. BMD and markers of bone turnover were measured at baseline and at 12 months.

RESULTS

After 12 months of treatment, there were statistically significant increases in BMD in both groups at all sites (all p < 0.05). For the lumbar spine, the increase in BMD was 2.3% for raloxifene compared with 5.8% for low-dose HRT and corresponding values for total body BMD were 2.9% for raloxifene and 4.6% for low-dose HRT; the increases being significantly greater in the low-dose HRT group (p < 0.001 and p = 0.02, respectively). Although the increase in BMD at the hip was significant for both raloxifene (2.1%) and low-dose HRT (3.2%) compared with baseline, the difference between the two regimens did not reach statistical significance. The decrease in serum C-terminal telopeptide fragment of type I collagen and serum osteocalcin levels for the low-dose HRT group (-53% and -47%, respectively) was significantly greater than for the raloxifene group (-23% and -27%, respectively; both p < 0.01).

CONCLUSIONS

In postmenopausal women with osteoporosis, low-dose HRT produced significantly greater increases in BMD of the lumbar spine and total body and greater decreases in bone turnover than raloxifene at 12 months.

Rationale for use of lower estrogen doses for postmenopausal hormone therapy

In placebo-controlled clinical trials low dose estrogens have been shown to reduce hot flashes an average of 65%. Low dosage is effective in preventing bone loss in early menopause and both low and ultralow estrogen dosages can prevent bone loss among women many years beyond menopause. Epidemiological studies indicate less risk of cardiovascular disease and venous thromboembolism in women who use low dose estrogens compared to standard dose. Low dosages of estrogens are less likely to produce unacceptable side effects, such as vaginal bleeding or breast tenderness. When prescribing low dosage estrogen, one can safely use less progestogen, either less daily dosage or less frequent cycles. Older women on ultralow estrogen may not require regular progestogen because the endometrium is not stimulated. In conclusion, there is a strong rationale for use of lower estrogen dosage in HT. Low dosage estrogen can relieve vasomotor symptoms and can prevent postmenopausal bone loss. Women taking low dosages of estrogens are less likely to have unacceptable side effects, such as vaginal bleeding or breast tenderness. Moreover, the potential harm caused by standard dosages of estrogen with progestin, including coronary heart disease, venous thromboembolism, stroke, and breast cancer may be mitigated by use of lower estrogen doses that do not require daily or monthly progestin opposition.

Unopposed estradiol therapy in postmenopausal women: results from two randomized trials

OBJECTIVE

To estimate the rates of endometrial hyperplasia, bleeding episodes, and interventions among menopausal women receiving unopposed oral estradiol or placebo therapy with ultrasound monitoring over 3 years.

METHODS

Two-hundred eighteen healthy women with intact uteri enrolled in the Estrogen in the Prevention of Atherosclerosis Trial (EPAT) or the Women's Estrogen-Progestin Lipid-Lowering Hormone Atherosclerosis Regression Trial (WELL-HART) were randomly assigned to either 1 mg of micronized 17beta-estradiol (n=96) or placebo (n=122) daily for up to 3 years in a double-blind fashion. Patients were followed with annual measurement of endometrial thickness using transvaginal ultrasonography. Logistic regression was used to identify predictors of uterine bleeding and endometrial biopsy.

RESULTS

Over the study periods, nine women (9.4% of patients, 95% confidence interval [CI] 3.6-15.2%) in the estradiol group developed hyperplasia. Eight of the nine cases (88.9%) of hyperplasia were simple without atypia. Women receiving estradiol were more likely than those receiving placebo to have at least one episode of uterine bleeding (67% versus 11% at 3 years, respectively, P<.001). Women in the estradiol group were also more likely to have an endometrial biopsy (48% versus 4% at 3 years, P<.001). Among women on estradiol, obesity (body mass index [BMI] greater than 30 kg/m(2)) significantly increased the odds of uterine bleeding compared with normal-weight patients (BMI 25 or less) (OR 3.7, 95% CI 1.2-11.8).

CONCLUSION

Short-term, unopposed estradiol therapy with gynecologic monitoring may be an option for the treatment of menopausal symptoms. Menopausal women choosing estradiol therapy, especially if obese, should anticipate uterine bleeding and the possibility of an endometrial biopsy.

CLINICAL TRIAL REGISTRATION

Clinicaltrials.gov, www.clinicaltrials.gov, NCT 00000559 and NCT 00115024.

LEVEL OF EVIDENCE

I.

Endometrial bleeding

Abnormal bleeding is a significant health problem, especially during adolescence and before menopause when anovulatory cycles are common. Curettage is rarely necessary to investigate or treat menstrual problems in adolescents, and its use should also be minimized in women younger than 40 years. In every age group, medical treatment is the initial choice, but surgical treatment by endometrial destruction or hysterectomy is sometimes required. Benign causes of bleeding include fibroids and possibly adenomyosis, but the indications for treatment in each case depend upon the extent of bleeding, not the extent of the lesion. Breakthrough bleeding (BTB) with combined oral contraceptives commonly leads to discontinuation of the method. As BTB tends to improve with time, in the first 3 months of pill use, unless there are obvious underlying causes, women should be reassured that it will likely settle. BTB is often the reason for discontinuing progestogen-only contraception, and there is a need for effective means of treating unscheduled bleeding. Bleeding occurs in approximately 3% of post-menopausal women, and the use of hormones increases the likelihood of bleeding by >5-fold. Knowledge of the underlying mechanisms of bleeding is essential to the development of effective treatment.

Endometrial effects of tibolone

BACKGROUND AND OBJECTIVES

The Tibolone Histology of the Endometrium and Breast Endpoints Study is a multicenter, randomized, double-blind study designed to address the conflicting reports in the literature about the endometrial safety of tibolone (1.25 or 2.5 mg/d). Tibolone was compared with continuous combined conjugated equine estrogen (CEE) plus medroxyprogesterone acetate (MPA) (0.625 + 2.5 mg/d).

METHODS

Subjects were randomized in a 1:1:2 ratio to tibolone 1.25 mg/d, 2.5 mg/d, and CEE/MPA, respectively. The one-sided 95% confidence interval (CI) has been evaluated for the incidence of abnormal endometrial histology (hyperplasia or carcinoma) and hyperplasia and carcinoma separately for each of the two treatment groups and the treatment groups combined after 1 and 2 yr of treatment with tibolone, compared with CEE/MPA.

RESULTS

A total of 3240 women were randomized, with 3224 receiving at least one dose of study medication. The incidence and upper one-sided 95% CI for the incidence of abnormal endometrium (hyperplasia or carcinoma), and hyperplasia and carcinoma separately, were calculated at end point, yr 1, and yr 2. The incidence (upper one-sided 95% CI) of abnormal endometrium at end point was 0.0 (0.5), 0.0 (0.4), and 0.2 (0.5) in the tibolone 1.25 mg, 2.5 mg, and CEE/MPA groups, respectively. During the entire treatment period, amenorrhea was reported more frequently with tibolone 1.25 mg (78.7%) and 2.5 mg (71.4%) than CEE/MPA (44.9%).

CONCLUSION

The Tibolone Histology of the Endometrium and Breast Endpoints Study results confirm previous findings that tibolone does not induce endometrial hyperplasia or carcinoma in postmenopausal women, and it is associated with a better vaginal bleeding profile than CEE/MPA.

Benefits and risks of long-term low-dose oral continuous combined hormone therapy

OBJECTIVES

Current recommendations for hormone therapy (HT) are mainly based on findings from studies using standard dose regimens in older women who had a different health profile from those who start HT soon after the onset of menopause.

METHODS

We, therefore, reviewed controlled trials assessing the efficacy, safety and tolerability of low-dose oral continuous combined HT (cc-HT) started for treatment of climacteric symptoms. This review is limited to oral cc-HT regimens over sequential regimens as most postmenopausal women prefer not to have a return of uterine bleeding, and to studies of at least 2 years in duration.

RESULTS

Low-dose cc-HT is effective in alleviating climacteric symptoms and in maintaining bone density over prolonged periods, although no data were available regarding fracture risk. No increased risk of coronary heart disease, venous thrombo-embolism or stroke during the use of low-dose cc-HT was reported in the long-term studies and no definitive evidence for an increased risk of breast cancer was found. Breakthrough bleeding during the first months of use is less common than with standard dose HT and amenorrhoea is achieved in most women over time. These regimens are safe for the endometrium and are well tolerated, with a low incidence of adverse events compared with standard doses.

CONCLUSIONS

Current evidence from controlled trials indicates that low-dose oral cc-HT appears effective and safe. This makes it a good choice for the alleviation of climacteric symptoms, and for this purpose long-term administration of low-dose cc-HT does not seem to impose serious health risks. However, more long-term study data and direct head-to-head comparisons between various low-dose preparations are needed to support or rectify the safety aspects.

Historical perspectives in postmenopausal hormone therapy: defining the right dose and duration

Recommended dosages of postmenopausal estrogen therapy (ET) and estrogen-progestin therapy (EPT), like those of oral contraceptives, have decreased markedly since oral estrogens were first introduced. Recently, the movement toward lower doses of ET/ EPT has accelerated because of the results of the Women's Health Initiative, which showed that lower-dose ET/EPT may provide similar efficacy and an improved safety profile compared with higher-dose preparations. For example, lower ET/EPT doses effectively relieve vasomotor and vulvovaginal symptoms associated with menopause, prevent bone loss, protect the endometrium, and are better tolerated than commonly prescribed doses. Current guidelines suggest the use of the lowest effective dose for the shortest duration consistent with treatment goals, benefits, and risks for the individual woman. However, the impact of treatment discontinuation should be considered when advising women to use hormone therapy for relieving menopausal symptoms for the shortest possible duration.

Molecular analysis of human endometrium: short-term tibolone signaling differs significantly from estrogen and estrogen + progestagen signaling

Tibolone, a tissue-selective compound with a combination of estrogenic, progestagenic, and androgenic properties, is used as an alternative for estrogen or estrogen plus progesterone hormone therapy for the treatment of symptoms associated with menopause and osteoporosis. The current study compares the endometrial gene expression profiles after short-term (21 days) treatment with tibolone to the profiles after treatment with estradiol-only (E₂) and E₂ + medroxyprogesterone acetate (E₂ + MPA) in healthy postmenopausal women undergoing hysterectomy for endometrial prolapse. The impact of E₂ treatment on endometrial gene expression (799 genes) was much higher than the effect of tibolone (173 genes) or E₂ + MPA treatment (174 genes). Furthermore, endometrial gene expression profiles after tibolone treatment show a weak similarity to the profiles after E₂ treatment (overlap 72 genes) and even less profile similarity to E₂ + MPA treatment (overlap 17 genes). Interestingly, 95 tibolone-specific genes were identified. Translation of profile similarity into biological processes and pathways showed that ER-mediated downstream processes, such as cell cycle and cell proliferation, are not affected by E2 + MPA, slightly by tibolone, but are significantly affected by E₂. In conclusion, tibolone treatment results in a tibolone-specific gene expression profile in the human endometrium, which shares only limited resemblance to E₂ and even less resemblance to E2 + MPA induced profiles.

Postmenopausal hormone replacement therapy: endometrial and breast effects

The history of hormone replacement therapy (HRT) dates back to the late 1800s, when animal extracts of ovaries were first used. With the development of synthetic hormones, widespread use in postmenopausal women extended throughout the industrialized world, so that by the late 1900s roughly one-third to one-half of all postmenopausal women in the United States and Europe were taking HRT. Two events changed the course of use of HRT: the association of an increased rate of endometrial carcinoma with estrogen-only HRT and the association of an increased breast cancer rate with combined estrogen and progestin HRT. This review explores the evidence of the effects of HRT on the endometrium and the breast, with emphasis on the pathologic changes.

Effects of tibolone and continuous combined conjugated equine estrogen/medroxyprogesterone acetate on the endometrium and vaginal bleeding: results of the OPAL study

OBJECTIVES

The primary objective of the Osteoporosis Prevention and Arterial effects of tiboLone study was to compare the effect of tibolone and placebo on the progression of the common carotid artery intima-medial thickness; the common carotid artery intima-medial thickness and bone data will be presented elsewhere. A secondary objective was to assess the effects of tibolone (2.5 mg), continuous combined conjugated equine estrogen/medroxyprogesterone acetate [0.625/2.5 mg], and placebo on the endometrium and vaginal bleeding; these results are the subject of this report.

STUDY DESIGN

This 3-year, three-arm, international, randomized, double-blind, parallel group, placebo-controlled clinical trial enrolled 866 postmenopausal women (aged 45-79 years). The endometrium was assessed by annual transvaginal ultrasound scans and end-of-study biopsies (United States/United Kingdom centers only). Vaginal bleeding was recorded in daily diaries.

RESULTS

Endometrial thickness measured by transvaginal ultrasound scan increased slightly during the first year with tibolone and conjugated equine estrogen/medroxyprogesterone acetate, without any further progression. After 3 years, there were no significant differences between the tibolone, conjugated equine estrogen/medroxyprogesterone acetate, and placebo groups in the incidence of proliferation (1.4%, 4.8%, and 0%, respectively), endometrial hyperplasia (0% in all groups), or cancer (1, 0, and 1 case, respectively). During the first 3 months, bleeding/spotting rates were greater with conjugated equine estrogen/medroxyprogesterone acetate (48%) than with tibolone (18%; P < .001) or placebo (3%; P < .001). During 3 years of treatment, the incidence of bleeding/spotting was 66%, 48%, and 23% for conjugated equine estrogen/medroxyprogesterone acetate, tibolone, and placebo, respectively. The mean number of bleeding/spotting days was greater in the conjugated equine estrogen/medroxyprogesterone acetate than the tibolone or placebo groups (61, 28, and 7 days, respectively; P = .023 vs tibolone; P < .0001 vs placebo). The mean number of bleeding/spotting episodes was also greater in the conjugated equine estrogen/medroxyprogesterone acetate group (13 episodes) compared with the tibolone group (six episodes; P < .001) and placebo group (four episodes; P < .001). Vaginal bleeding was more commonly reported as an adverse event with conjugated equine estrogen/medroxyprogesterone acetate than tibolone (26.4% vs 10.8%, P < .0001) and as the reason for premature discontinuation (9% vs 2%, P = .001).

CONCLUSION

Compared with conjugated equine estrogen/medroxyprogesterone acetate, tibolone has a better tolerability profile with respect to vaginal bleeding but with a similar endometrial safety. These results reinforce the endometrial safety profile of tibolone.

Development of low-dose reproductive hormone therapies in China

A historical account is presented of the development of sex hormone treatment from its beginning at the Peking Union Medical College to its present-day generalization throughout China. The general theme of this work has been to test low-dose hormone regimens. Notable successes include low-dose oral contraception and menopausal hormone treatment. In support of the latter, we present a new clinical study of the effects of low-dose, intermittent, patient-metered hormone replacement therapy (HRT), which shows decreased menopausal symptoms, maintenance of bone health and height, and improved cardiovascular status compared with untreated controls. Cardiovascular testing, included carotid artery ultrasound scanning and computed tomographic coronary angiography, supports a cardioprotective effect of long-term (up to 31 years) low-dose HRT that is begun during the menopausal transition. These results highlight the urgent need for larger, prospective trials of long-term low-dose HRT started during the perimenopausal period.

Hormone replacement therapy in menopausal women: Past problems and future possibilities

Oral administration of conjugated equine estrogens (CEE) with and without the synthetic progestin medroxyprogesterone acetate (MPA) in postmenopausal women is associated with side-effects that include increased risk of stroke and breast cancer. The current evidence that transdermal administration of estradiol may provide a safer alternative to orally administered CEE is reviewed. Transdermally administered estradiol has been shown to be an efficacious treatment for hot flushes possibly without the increase in blood clotting that is associated with administration of oral CEE. Further, natural progesterone may have a more beneficial spectrum of physiological effects than synthetic progestins. The substantial differences between CEE compared with estradiol and estriol, as well as the differences between synthetic MPA and natural progesterone, are detailed. Estriol is an increasingly popular alternative hormone therapy used for menopausal symptoms. There is evidence that estriol, by binding preferentially to estrogen receptor-beta, may inhibit some of the unwanted effects of estradiol. New clinical trials are needed to evaluate the safety and efficacy of topically or transdermally administered combinations of estradiol, estriol and progesterone. Future studies should focus on relatively young women who begin estrogen supplement use near the start of menopause.

Chronic progesterone antagonist-estradiol therapy suppresses breakthrough bleeding and endometrial proliferation in a menopausal macaque model

BACKGROUND

Clinicians routinely prescribe progestins along with estrogens during menopausal hormone therapy (HT) to block estrogen-dependent endometrial proliferation. Breakthrough bleeding (BTB) can negate the utility of this treatment. Because progestin antagonists also inhibit estrogen-dependent endometrial proliferation in women and macaques, we used a menopausal macaque model to determine whether a potent progestin antagonist (ZK 230 211, Schering AG; ZK) combined with estrogen would provide a novel mode of HT.

METHOD

Ovariectomized rhesus macaques were treated for 5 months with either estradiol (E(2)) alone, E(2) + progesterone (two doses) or E(2) + ZK (0.01, 0.05 or 0.25 mg/kg).

RESULTS

In the E(2) + progesterone groups, progesterone suppressed endometrial proliferation and induced a thick decidualized endometrium. In the E(2) + ZK 230 211 groups, all doses of ZK blocked endometrial proliferation and induced endometrial atrophy. In all ZK-treated groups, the atrophied endometrium contained some dilated glands lined by an inactive, flattened, non-mitotic epithelium. BTB was much lower in the E(2) + ZK groups (17 days of spotting, all groups) than in the E(2) and E(2) + progesterone groups (155 bleeding days, all groups). ZK suppressed E(2) effects in the cervix, but not in the vagina, oviduct or mammary glands. All serum chemistry and lipid profiles were normal.

CONCLUSION

The ability of ZK to block estrogen-dependent endometrial proliferation, induce endometrial atrophy and suppress BTB in a menopausal macaque model indicates that progestin antagonists may provide a novel mode of HT.

Histological and immunohistochemical evaluation of postmenopausal endometrium after 3 weeks of treatment with tibolone, estrogen only, or estrogen plus progestagen

OBJECTIVE

To evaluate histological and immunohistochemical parameters of short-term (21 days) tibolone, estrogen-only, and estrogen+progestagen treatment in the human postmenopausal endometrium.

DESIGN

An observational, open, nonrandomized, controlled study.

SETTING

Three collaborating centers: Amphia Hospital in Breda, Albert Schweitzer Hospital in Dordrecht, Erasmus Medical Center in Rotterdam, the Netherlands.

PATIENT(S)

Thirty healthy, postmenopausal women.

INTERVENTION(S)

Control group (n = 9), no hormonal treatment; tibolone group (n = 8), patients were treated with 2.5 mg of tibolone (administered orally) every day, starting 21 days before surgery; estrogen group (n = 7), patients were treated with 2 mg of E(2) (Zumenon, administered orally; Zambon, Amerfoort; The Netherlands) every day, starting 21 days before surgery; estrogen+progestagen group (n = 6), patients were treated with 2 mg of E(2) (Zumenon, administered orally) and 5 mg of medroxyprogesterone acetate (administered orally) every day, starting 21 days before surgery.

MAIN OUTCOME MEASURE(S)

Uterine tissues were collected, and two pathologists independently assessed histology. Immunohistochemical parameters measured were estrogen receptor alpha, progesterone receptor A/B, Hoxa10, Ki67, and Bcl-2.

RESULT(S)

On the basis of a number of histological and immunohistochemical parameters measured after 21 days of treatment, it was observed that tibolone displays clearly less stimulation (proliferation) of the human postmenopausal endometrium than estrogen at the beginning of a treatment, but the stimulation is higher than with estrogen+progestagen.

CONCLUSION(S)

Short-term (21 days) tibolone treatment results in a small stimulation of proliferation of the endometrium, and because long-term treatment with tibolone has been demonstrated to lead to an atrophic endometrium, it may be concluded that the stimulatory effect, as observed in this study, is transient in nature. It is hypothesized that tibolone first displays a more estrogenic mode of action, which over time, is counterbalanced by the induction of its progestagenic properties.

Randomized trial comparing low-dose hormone replacement therapy and HRT plus 1alpha-OH-vitamin D3 (alfacalcidol) for treatment of postmenopausal bone loss

We conducted a prospective, randomized, multicenter, open-label 2-year trial with 76 postmenopausal women aged > or =60 years with low (T-score less than -1) lumbar bone mineral density (BMD). The hormone replacement therapy (HRT) group received a low dose of conjugated estrogen (CEE) at a dose of 0.31 mg/day +/- medroxyprogesterone acetate (MPA) 2.5 mg/day. Group HRT/D received the same dose of HRT together with alfacalcidol in a daily dose of 1.0 microg/day. Changes in lumbar BMD measured by dual energy X-ray absorptiometry (DXA) were followed every 6 months for 2 years. The lumbar BMD of group HRT increased 3.37% [95% confidence interval (CI) 1.6%-5.2%], 4.00% (95%CI 1.6%-6.4%), and 2.32% (95%CI -0.7% to 5.3%) at 12, 18, and 24 months, respectively, when the baseline value was taken as 0%. Lumbar BMD of group HRT/D showed a significant increase beyond 6 months. The percent increases for this group at 6, 12, 18, and 24 months were 6.18 (95%CI 1.3%-6.6%), 6.18% (95%CI 3.9%-8.5%), 7.17% (95%CI 4.3%-10.0%), and 8.75% (95%CI 6.0%-11.5%), respectively. In addition, there was a significant difference in the changes of the lumbar BMD between the two groups at 24 months, suggesting that the combination of HRT and alfacalcidol is more effective than HRT alone in terms of the BMD effect. This study is the first prospective trial demonstrating an additive effect of alfacalcidol on lumbar BMD in postmenopausal women receiving low-dose HRT. It suggests that the combination therapy can be considered to be a promising mode of treatment for bone loss after menopause.

Low-dose estrogen therapy for prevention of osteoporosis: working our way back to monotherapy

The risks of low bone mineral density, osteoporosis and fractures, are major concerns in postmenopausal women. Although postmenopausal hormone therapy is effective for reducing these risks, safety issues have been raised by the results of studies such as the Women's Health Initiative. Although there are scientifically valid reasons to be wary of the general applicability of the Women's Health Initiative findings, the study has underscored the continuing need for research into new forms of menopausal hormone therapy. Low-dose transdermal estrogen monotherapy can preserve bone density while relieving vasomotor symptoms. Transdermal administration may offer advantages, including lack of first-pass liver metabolism, which permits the use of lower doses and avoids a negative impact on the lipid profile. Moreover, a recently published 2-year study of ultra-low-dose transdermal estrogen monotherapy in an older population similar to that of the WHI reported significant increases in bone mineral density, accompanied by significant reductions in markers of bone turnover, with no increased risk of endometrial hyperplasia or other side effects. Additional studies are warranted to shed further light on the possible benefits of low-dose estrogen monotherapy for the prevention of bone loss in postmenopausal women.

Vasomotor symptom relief versus unwanted effects: role of estrogen dosage

Recent clinical trials show that low-dose estrogen reduces the number of moderate to severe vasomotor episodes by 65%. This reduction is about midway between the 35% to 40% reduction observed with placebo and the 75% to 80% reduction observed with standard dosage. Compared with standard dosages whose effects are substantial by 4 weeks, relief with lower dosages is not maximal until 8 to 12 weeks. Women using lower dosages of estrogen experience 50% lower rates of irregular bleeding or breast tenderness compared with individuals taking standard dosages. Despite several lower dosage hormone therapy (HT) formulations being approved by the US Food and Drug Administration (FDA) and brought to market, their uptake by healthcare providers has been slow. Most women who have continued HT after reports of the Women's Health Initiative (WHI) were published take estrogen at the standard dosage; only a minority of these individuals report receiving guidance about switching to a lower dosage. The purpose of this review is to summarize the clinical trial data showing, on one hand, effects of various dosages of estrogen on vasomotor symptoms and, on the other hand, the effects of these same doses on troublesome adverse events, particularly vaginal bleeding or breast tenderness. It is time to reconsider the current estrogen dosage recommendation on the basis of symptom benefit versus symptom nuisance. Furthermore, healthcare providers need to learn how and when to prescribe lower dosages of HT to optimize patient acceptance and continuation.

Sample size and power analysis for endometrial safety studies

Endometrial safety studies are required for the approval of progestin components. The Committee for Proprietary Medicinal Products requirement is the actual percentage below 2% and the upper limit of the one-sided exact 95% confidence interval not more than 2% above the point estimate. The more recent U.S. Food and Drug Administration requirement is the actual percentage < or = 1% and the upper limit of the one-sided exact 95% confidence interval < or =4%. I studied the sample size and power needed to satisfy both requirements based on the exact confidence intervals for the binomial parameter and the Poisson parameter. I discovered that a larger sample size does not always lead to a higher power. I presented a best sample size that satisfies both requirements and recommended that the patient enrollment should be closely monitored during the study.