Effects of hormone replacement on hemostasis in spontaneous menopause

Hormone therapy and hemostasis among postmenopausal women: a review

OBJECTIVE

Postmenopausal hormone therapy (HT), which consists of exogenous estrogens with or without combined progestogens, remains the most effective treatment of climacteric symptoms. Depending on its characteristics, it may nevertheless increase the risk of venous thromboembolism, and its effects on hemostasis have been studied for several decades. The aim of this review was to summarize current knowledge on the effects of HT on hemostasis, taking into account the route of estrogen administration, the daily dose and chemical structure of estrogens, and the pharmacologic class of progestogens.

METHODS

Data from randomized controlled trials that included a control group (either placebo or no treatment) were selected, and analysis was conducted on different generations of biomarkers.

RESULTS

Overall, studies showed a hemostasis imbalance among oral estrogen users with a decrease in coagulation inhibitors and an increase in markers of activation coagulation, leading to global enhanced thrombin generation. By contrast, transdermal estrogen use was associated with less change in hemostasis variables and did not activate coagulation and fibrinolysis. No clear difference in HT effects on hemostasis was highlighted between daily doses of estrogens, between estrogen compounds, and between pharmacologic classes of progestogens.

CONCLUSIONS

Changes in hemostasis are in accordance with clinical results showing an increased thrombotic risk with oral--but not transdermal--estrogen use.

Effect of two oral doses of 17beta-estradiol associated with dydrogesterone on thrombin generation in healthy menopausal women: a randomized double-blind placebo-controlled study

Oral hormone therapy is associated with an increased risk of venous thrombosis. Drug agencies recommend the use of the lowest efficient dose to treat menopausal symptoms for a better risk/ratio profile, although this profile has not been totally investigated yet. The aim of the study was to compare the effect of the standard dose of 17beta-estradiol to a lower one on thrombin generation (TG). In a 2-month study, healthy menopausal women were randomized to receive daily 1mg or 2 mg of 17beta-estradiol (E1, n = 24 and E2, n = 26; respectively) with 10 mg dydrogesterone or placebo (PL, n = 22). Plasma levels factors VII, X, VIII and II were assessed before and after treatment as well as Tissue factor triggered TG, which allows the investigation of the different phases of coagulation process. The peak of thrombin was higher in hormone therapy groups (E1: 42.39 +/- 50.23 nm, E2: 31.08 +/- 85.86 nm vs. 10.52 +/- 40.63 nm in PL, P = 0.002 and P = 0.01). Time to reach the peak was also shortened (PL: 0.26 +/- 0.69 min vs. E1: -0.26 +/- 0.80 min, E2: -0.55 +/- 0.79 min, P <10(-3) for both comparisons) and mean rate index of the propagation phase of TG was significantly increased. Among the studied clotting factors, only the levels of FVII were significantly increased after treatment administration. The two doses of 17beta-estradiol induced in a similar degree an acceleration of the initiation and propagation phase of tissue factor triggered thrombin generation and a significant increase of FVII coagulant activity.

Comparison of the effects of tibolone and estrogen therapy on hemostasis in surgical menopause: a randomized, double-blind, placebo-controlled study

OBJECTIVE

To examine the effects of unopposed estrogen (E) and tibolone therapy on coagulation and natural anticoagulant systems in surgical menopause.

DESIGN

A randomized, double-blind, placebo-controlled study.

SETTING

University hospital clinic in Turkey.

PATIENT(S)

Ninety healthy surgically postmenopausal women.

INTERVENTION(S)

Ninety surgically postmenopausal women were randomized into three groups: unopposed conjugated ET (0.625 mg/d, group 1), tibolone (2.5 mg/d, group 2), and identical tablets of placebo (group 3).

MAIN OUTCOME MEASURE(S)

Effects on parameters in the clotting cascade at baseline and after 24 weeks of treatment.

RESULT(S)

After 6 months, fibrinogen, lipoprotein (a), and factor VIIa were decreased, and activated partial thromboplastin time was increased significantly in the ET group compared with in the placebo group. However, tibolone significantly decreased only the serum levels of factor VIIa and factor IX and prolonged the activated partial thromboplastin time, compared with placebo group. In addition, conjugated ET caused a significantly greater decrease in serum fibrinogen level than did tibolone.

CONCLUSION(S)

Neither E nor tibolone therapy led to activation of coagulation in the surgically menopausal women. Both preparations changed the overall hemostatic balance to a more fibrinolytic state.

Complex actions of sex steroids in adipose tissue, the cardiovascular system, and brain: Insights from basic science and clinical studies

Recent publications describing the results of the Women's Health Initiative (WHI) and other studies reporting the impact of hormone therapy on aging women have spurred reexamination of the broad use of estrogens and progestins during the postmenopausal years. Here, we review the complex pharmacology of these hormones, the diverse and sometimes opposite effects that result from the use of different estrogenic and progestinic compounds, given via different delivery routes in different concentrations and treatment sequence, and to women of different ages and health status. We examine our new and growing appreciation of the role of estrogens in the immune system and the inflammatory response, and we pose the concept that estrogen's interface with this system may be at the core of some of the effects on multiple physiological systems, such as the adipose/metabolic system, the cardiovascular system, and the central nervous system. We compare and contrast clinical and basic science studies as we focus on the actions of estrogens in these systems because the untoward effects of hormone therapy reported in the WHI were not expected. The broad interpretation and publicity of the results of the WHI have resulted in a general condemnation of all hormone replacement in postmenopausal women. In fact, careful review of the extensive literature suggests that data resulting from the WHI and other recent studies should be interpreted within the narrow context of the study design. We argue that these results should encourage us to perform new studies that take advantage of a dialogue between basic scientists and clinician scientists to ensure appropriate design, incorporation of current knowledge, and proper interpretation of results. Only then will we have a better understanding of what hormonal compounds should be used in which populations of women and at what stages of menopausal/postmenopausal life.

Meta-analysis: effect of hormone-replacement therapy on components of the metabolic syndrome in postmenopausal women

AIM

To quantify the effects of hormone-replacement therapy (HRT) on components of the metabolic syndrome in postmenopausal women.

METHODS

Comprehensive searches of electronic databases were performed from April 1966 to October 2004. We included randomized controlled trials that were of at least 8 weeks duration and evaluated the effect of HRT on metabolic, inflammatory or thrombotic components. Insulin resistance was calculated by homeostasis model assessment (HOMA-IR). Subgroup analysis evaluated the effects for transdermal and oral treatment and for diabetic and non-diabetic women.

RESULTS

Pooled results of 107 trials showed that HRT reduced abdominal fat [-6.8% (CI, -11.8 to -1.9%)], HOMA-IR [-12.9% (CI, -17.1 to -8.6%)] and new-onset diabetes [relative risk 0.7 (CI, 0.6-0.9)] in women without diabetes. In women with diabetes, HRT reduced fasting glucose [-11.5% (CI, -18.0 to -5.1%)] and HOMA-IR [-35.8% (CI, -51.7 to -19.8%)]. HRT also reduced low-density lipoprotein/high-density lipoprotein cholesterol ratio [-15.7% (CI, -18.0 to -13.5%)], lipoprotein(a) [Lp(a)] [-25.0% [CI, -32.9 to -17.1%)], mean blood pressure [-1.7% (CI, -2.9 to -0.5%)], E-selectin [-17.3% (CI, -22.4 to -12.1%)], fibrinogen [-5.5% (CI, -7.8 to -3.2%)] and plasminogen activator inhibitor-1 [-25.1% (CI, -33.6 to -15.5%)]. Oral agents produced larger beneficial effects than transdermal agents, but increased C-reactive protein (CRP) [37.6% (CI, 17.4-61.3%)] and decreased protein S [-8.6% CI, -13.1 to -4.1%)], while transdermal agents had no effect.

CONCLUSIONS

HRT reduces abdominal obesity, insulin resistance, new-onset diabetes, lipids, blood pressure, adhesion molecules and procoagulant factors in women without diabetes and reduced insulin resistance and fasting glucose in women with diabetes. Oral agents adversely affected CRP and protein S, while transdermal agents had no effects.

Transdermal estradiol does not impair hemostatic biomarkers in postmenopausal women

OBJECTIVE

To evaluate the effect of transdermal estradiol therapy (ET) on coagulation and fibrinolysis markers in postmenopausal women.

METHODS

Prospective open trial study in 59 healthy hysterectomized postmenopausal women. Thirty women received transdermal ET (50 microg per day) during 3 months and 29 women formed the untreated arm.

RESULTS

Baseline factor VII-tissue factor complex (VIIa-rTF), fibrinogen and plasminogen activator inhibitor-1 (PAI-1) levels decreased significantly (P < 0.01) after therapy. In contrast, tissue-type plasminogen activator antigen (t-PA) levels increased significantly (P < 0.01). After ET, there was no difference in protein C activity (PC), protein S activity (PS), plasminogen (PLG), and antithrombin III (ATIII) levels. None of participants reported thromboembolic events.

CONCLUSION

ET elicited a decrement in blood biomarkers implicated in coagulation activation which in turn seemed to improve fibrinolytic activity. These results suggest that transdermal route does not impair thrombotic risk.

Short-term effects of estrogen, tamoxifen and raloxifene on hemostasis: a randomized-controlled study and review of the literature

INTRODUCTION

Estrogen therapy (ET), tamoxifen and raloxifene are associated with a two- to three-fold increased risk of venous thrombosis (VT); however, the mechanisms by which each drug increases venous thrombosis propensity are not fully understood. The objectives of this investigation were to compare the effects of these three treatments on hemostasis in a head to head randomized placebo-controlled trial.

PATIENTS/METHODS

Ninety-four postmenopausal women were assigned to receive oral estrogen (conjugated equine estrogen [CEE] 0.625 mg, n=23), tamoxifen 20 mg (n=24), raloxifene 60 mg (n=24) or placebo (n=23) daily for 6 months. Blood samples were analyzed for procoagulant factors (prothrombin, factors VII [fVII], VIII [fVIII], IX [fIX] and XI [fXI], D-dimer and von Willebrand factor [vWf]), anticoagulant factors (antithrombin [AT], total and free protein S, protein C and activated protein C [APC] resistance) and fibrinolytic factors (thrombin activatable fibrinolysis inhibitor [TAFI] and plasminogen activator inhibitor-1 [PAI-1]), at baseline and at 6 months of treatment.

RESULTS

Estrogen increased factor VII and D-dimer, and decreased antithrombin, total and free protein S and PAI-1. Changes with tamoxifen were distinct from estrogen with increases in factors VIII, IX, vWf and free protein S, and decreases in AT, total protein S, protein C and plasminogen activator inhibitor-1. Raloxifene produced similar effects as tamoxifen, but did not increase factor IX or decrease protein C.

CONCLUSIONS

Estrogen, tamoxifen and raloxifene affected hemostasis favoring procoagulation and impairing anticoagulation. The biochemical effects of the selective estrogen receptor modulators (SERMs) were distinct from those of estrogen and differed only subtly from each other.

Progestogens of varying androgenicity and cardiovascular risk factors in postmenopausal women receiving oestrogen replacement therapy

OBJECTIVE

Medroxyprogesterone (MP) was used as the progestogen in randomized clinical trials of postmenopausal hormone replacement on cardiovascular risk. To attempt to understand the lack of benefit in these trials, we have examined the effects of MP and two other progestogens, the less androgenic desogestrel (DG) and the more androgenic norethisterone (NE), on cardiovascular risk factors against a background of oestrogen therapy.

DESIGN AND MEASUREMENTS

Thirty-four women were treated with conjugated equine oestrogens (CEE) 0.625 mg daily alone for 12 weeks, followed in random order by each of the three progestogens (DG 75 microg, MP 10 mg and NE 1 mg daily) given sequentially for three 12-week cycles while maintaining the same CEE treatment. We measured serum lipoproteins, paraoxonase activity, C-reactive protein (CRP), fibrinogen, fasting glucose and insulin levels at baseline, at the end of the oestrogen-only phase and at the end of each of the combined oestrogen and progestogen phases.

RESULTS

The addition of progestogens to CEE maintained the oestrogen-induced reduction in apolipoprotein B (apo B) and lipoprotein (a) [Lp(a)], and further lowered total cholesterol (P < 0.01) and fibrinogen (P < 0.001). CEE raised serum triglyceride (P < 0.001) and CRP (P < 0.01) concentrations, which reverted towards pre-oestrogen levels with progestogens. Progestogens significantly reduced high density lipoprotein (HDL) cholesterol (P < 0.05). NE was associated with the greatest reduction in HDL cholesterol and apo A1, but was most effective in preserving paraoxonase activity and reducing the potentially unfavourable oestrogen-induced increases in triglycerides and CRP.

CONCLUSION

Preconceptions that more androgenic progestogens necessarily have more unfavourable effects on cardiovascular risk factors may require revision.

Mortality associated with hormone replacement therapy in younger and older women: a meta-analysis

OBJECTIVE

To assess mortality associated with hormone replacement in younger and older postmenopausal women.

DESIGN

A comprehensive search of MEDLINE, CINAHL, and EMBASE databases was performed to identify randomized controlled trials of hormone replacement therapy from 1966 to September 2002. The search was augmented by scanning selected journals through April 2003 and references of identified articles. Randomized trials of greater than 6 months' duration were included if they compared hormone replacement with placebo or no treatment, and reported at least 1 death.

MEASUREMENTS

Outcomes measured were total deaths and deaths due to cardiovascular disease, cancer, or other causes. Odds ratios (OR) for total and cause-specific mortality were reported separately for trials with mean age of participants less than and greater than 60 years at baseline.

MAIN RESULTS

Pooled data from 30 trials with 26,708 participants showed that the OR for total mortality associated with hormone replacement was 0.98 (95% confidence interval [CI], 0.87 to 1.12). Hormone replacement reduced mortality in the younger age group (OR, 0.61; CI, 0.39 to 0.95), but not in the older age group (OR, 1.03; CI, 0.90 to 1.18). For all ages combined, treatment did not significantly affect the risk for cardiovascular or cancer mortality, but reduced mortality from other causes (OR, 0.67; CI, 0.51 to 0.88).

CONCLUSIONS

Hormone replacement therapy reduced total mortality in trials with mean age of participants under 60 years. No change in mortality was seen in trials with mean age over 60 years.

Differential effects of oral and transdermal estrogen/progesterone regimens on sensitivity to activated protein C among postmenopausal women: a randomized trial

OBJECTIVE

Activated protein C (APC) resistance not related to the factor V Leiden mutation is a risk factor for venous thrombosis. Oral estrogen replacement therapy (ERT) has been reported to induce APC resistance. Little is known about the effect of transdermal estrogen.

METHODS AND RESULTS

We enrolled 196 postmenopausal women who were randomly allocated to receive either 1 mg 17beta-estradiol orally (n=63) or 50 microg 17beta-estradiol transdermally per day (n=68), both associated with 100 mg progesterone daily or placebo (n=65) for 6 months. An activated partial thromboplastin time (APTT)-based test and the effect of APC on thrombin potential (ETP) were used. Oral ERT induced an ETP-based APC resistance compared with both placebo (P=0.006) and transdermal ERT (P<0.001), but there was no significant effect of transdermal ERT compared with placebo (P=0.191). There was no significant effect of ERT on the APTT-based APC sensitivity ratio. Prothrombin fragment 1+2 plasma levels were significantly higher after 6 months of treatment in women allocated to oral ERT compared with those on placebo and transdermal ERT and were positively and significantly correlated with changes in ETP-based APC sensitivity ratio.

CONCLUSIONS

Our data show that oral, unlike transdermal, estrogen induces APC resistance and activates blood coagulation. These results emphasize the importance of the route of estrogen administration.

Effect of oral and transdermal estrogen replacement therapy on hemostatic variables associated with venous thrombosis: a randomized, placebo-controlled study in postmenopausal women

OBJECTIVE

The purpose of this study was to investigate whether the effect of transdermal estrogen therapy in postmenopausal women differs from that of oral therapy with regard to resistance to activated protein C (APC), an important risk factor for venous thrombosis, and levels of related proteins, such as protein S, protein C, and prothrombin.

METHODS AND RESULTS

In a randomized, double-blind, placebo-controlled study, 152 healthy hysterectomized postmenopausal women received daily either placebo (n=49), transdermal 17beta-estradiol (E2) 50 microg (tE2 group, n=33), oral E2 1 mg (oE2 group, n=37), or oral E2 1 mg combined with gestodene 25 microg (oE2+G group, n=33) for 13 28-day treatment cycles, followed by 4 cycles of placebo for each group. Plasma samples were collected at baseline and in cycles 4, 13, and 17. In cycle 13, significant increases versus baseline and placebo were found in normalized APC sensitivity ratios (nAPCsr) in all treated groups (tE2, +26.9%; oE2, +102.7%; oE2+G, +69.9%). Increases in nAPCsr were significantly higher in the oral treatment groups than in the tE2 group. In addition, compared with baseline and placebo, after 13 cycles, decreases were observed in total protein S (tE2, -4.1%; oE2, -7.9%; oE2+G, -5.8%), free protein S (tE2, -7.1%; oE2, -8.4%; oE2+G, -5.2%), and protein C in the oE2+G group (-6.4%), but these changes did not explain the increase in nAPCsr. Changes in prothrombin were small and also did not affect the nAPCsr.

CONCLUSIONS

Increases were observed in resistance to APC, which were more pronounced in the oral treatment groups than in the transdermal group. The increase in resistance to APC was not explained by changes in protein S, protein C, or prothrombin and may contribute to the increased incidence of venous thrombosis in users of hormone replacement therapy.

Hormone therapy and venous thromboembolism

Convincing data from randomized trials and observational studies have demonstrated a two- to threefold increased risk of venous thromboembolism (VTE) with the use of hormone replacement therapy (HRT) in post-menopausal women. This risk is highest in the first year of use, but an increased risk persists after the first year if HRT use is ongoing. The risk of VTE is increased for oral oestrogen alone, oral oestrogen combined with progestin and probably for transdermal HRT. There is an increase in both idiopathic and non-idiopathic VTE with HRT. Early evidence suggests an interaction of HRT with thrombophilic states such as the factor V Leiden mutation, resulting in a synergistic increase in the risk of VTE. There is also an increased risk of VTE with raloxifene and tamoxifen, but the effects of low-dose HRT and tibolone on VTE risk are less clear.

Effects of Bak Foong Pill on blood coagulation and platelet aggregation

The effects of Bak Foong Pill (BFP, also known as Bai Feng Wan), a preparation of crude drugs in wide clinical use for treatment of gynecological disorders, on blood coagulation and platelet aggregation were investigated. The anticoagulant effect of BFP was evaluated by using thrombin time (TT), prothrombin time (PT), and activated partial thromboplastin time (APTT) assays. Results showed that BFP 70% ethanol extract (BFP-E-ext) significantly prolonged the TT in a dose-dependent manner with values of 17.6, 38.3, and 50.4 s at concentrations of 4.0, 6.0, and 12.0 mg/ml, respectively. Whereas, the BFP-E-ext did not show significant prolonging effect in PT and APTT assays. The results suggest that the anticoagulant effect of BFP is mediated by directly blocking thrombin, the key enzyme in the blood coagulation cascade. BFP-E-ext significantly inhibited platelet aggregation induced by collagen and adenosine diphosphate (ADP) with inhibition percentages of 74 and 52% at a concentration of 6.0 mg/ml, respectively, whereas, it exhibited a weak inhibitory activity on platelet aggregation induced by archidonic acid (AA). Comparing to BFP-E-ext, the effects of BFP aqueous extract (BFP-W-ext) on both anticoagulant and antiplatelet activities were significantly less potent. Moreover, the effects of the 26 ingredients of BFP on blood coagulation and platelet aggregation were separately evaluated with 19 ingredient herbs exhibiting anticoagulant effect and 10 exhibiting antiplatelet effect. The anticoagulant and antiplatelet effects of BFP were collectively demonstrated by in vivo assays showing prolonged bleeding times after BFP treatment for two weeks. The results of the present studies may provide explanations for beneficial effects of BFP on the circulation and indicate its potential use for cardiovascular diseases.

Increased resistance to activated protein C after short-term oral hormone replacement therapy in healthy post-menopausal women

As hormone replacement therapy is associated with an early excess risk of venous thrombosis, we investigated the effect of different oral hormone replacement therapies on resistance to activated protein C, and on levels of factor VIII antigen (FVIII:Ag) and factor XI antigen (FXI:Ag). In a prospective, randomized, placebo-controlled 12-week study, 60 healthy post-menopausal women daily received either placebo (n = 16) or 2 mg of micronized 17beta-oestradiol, either alone (E2, n = 16) or sequentially combined with dydrogesterone 10 mg (E2 + D, n = 14) or trimegestone 0.5 mg (E2 + T, n = 14). Medication was given orally. Normalized activated protein C sensitivity ratios (nAPCsr) were determined by quantifying the effect of activated protein C on the endogenous thrombin potential. FVIII:Ag and FXI:Ag were determined by enzyme-linked immunosorbent assay. Compared with baseline and placebo, the nAPCsr increased (92% to 142%; all P < 0.001) in all active treatment groups after both 4 and 12 weeks. Compared with placebo, hormone replacement therapy was not associated with significant changes in FVIII:Ag. After 4 and 12 weeks, FXI:Ag levels were significantly decreased in the E2 group (mean percentage changes from baseline versus placebo: -15.0%, P = 0.001 at 4 weeks and -16.6%, P = 0.003 at 12 weeks) and in the E2 + D group (-10.4%, P = 0.02 and -10.4%, P = 0.02). In conclusion, all hormone replacement regimens were associated with a large increase in resistance to activated protein C. In contrast, hormone replacement therapy had no effect on FVIII:Ag. Oral E2 and E2 + D had a small, favourable effect on FXI:Ag.

The mechanisms of thrombotic risk induced by hormone replacement therapy

OBJECTIVES

To review the available information on the action of hormones on the mechanisms involved in thrombotic risk.

RESULTS AND CONCLUSIONS

Thrombosis plays a crucial role in the genesis and progression of both coronary heart disease (CHD) and venous thromboembolic disease (VTED), the two main forms of cardiovascular disease. Two main determinants of the thromboembolic phenotype, hypercoagulable state and altered endothelium, accumulate much of the work performed on the influence of hormones on thrombosis. Information has accumulated mainly for oestrogens, but increasing evidences support a role for progestogens. The sensitivity of each of the three components of the hemostatic balance, the coagulation cascade, the anticoagulant system and fibrinolysis, to oestrogens has been widely examined in the literature. Functional tests suggest that HRT is accompanied by a procoagulant state. Much of the work has concentrated on changes induced on reputable indicators of risk for either CHD or VTED. Distinct indicators of increased coagulability, such as resistance to activated C protein, antithrombin or tissue factor pathway inhibitor have been selected for VTED, whereas factor VII, fibrinogen, and defective fibrinolysis, for CHD. Different states of genetic susceptibility have been involved in both forms of the disease. The status of health of endothelium, defines another scenario for attention in CHD. A long-term anti-atherogenic action of oestrogens, which may be associated with short-term risk in cases of atherosclerosis-induced endothelial dysfunction, may most adequately explain much of the clinical observation. In both CHD and VTED, the procoagulant changes initiate soon after HRT administration.