Conventional-dose hormone therapy (HT) and tibolone, but not low-dose HT and raloxifene, increase markers of activated coagulation

Interaction between apigenin and sodium deoxycholate with raloxifene: A potential risk for clinical practice

Apigenin (API) and sodium deoxycholate (NaDC) have different pharmacodynamic properties and can affect pharmacokinetics of drugs without causing significant toxicity. The aim of our study was to investigate the effect of API and NaDC on raloxifene pharmacokinetics in rats as well as on hemostasis parameters after applying the raloxifene therapeutic dose. Rats were treated daily with oral single dose of saline solution (1 ml/kg), API (10 mg/kg) and/or NaDC (4 mg/kg) for 7 days. Raloxifene was given orally or intravenously in a single dose (6 mg/kg) and during period of 24 h blood samples, feces and urine samples were collected. Blood samples were collected at the 15th, 30th, 45th, 60th, 90th minute and 2, 3, 4, 6, 8, 10, 12 and 24 h after raloxifene administration. Urine and feces samples were collected in the 3th, 6^h, 12th and 24th hour of the experiment. Rats were divided into 10 groups each of which contained 6 animals. Differences were considered statistically significant if p<0.05. Pretreatment with NaDC and API affected raloxifene pharmacokinetic profile after intravenous application. NaDC lead to statistically significant decrease in raloxifene serum concentration and increased volume of distribution and clearance as well as halftime of elimination, while API has also decreased also raloxifene serum concentrations and increased volume of distribution but not as profoundly as NaDC alone. Difference was also noticed in clearance where it was significantly increased in group pretreated with NaDC and slightly decreased in group pretreated with API. NaDC and API increased raloxifene amount in feces, both after peroral (p<0.05) and intravenous application. However, peroral application of raloxifene did not produce measurable raloxifene serum concentration in neither of investigated groups. NaDC shortened activated partial thromboplastin time (aPTT) and prothrombin time (PT). API reduced aPTT, PT and d-dimer level. Fibrinogen level was significantly increased in all experimental groups. Both NaDC and apigenin had significant influence on raloxifene pharmacokinetics and can potentiate the raloxifene effects on hemostasis parameters, by increasing its bioavailability. These substances may be the subject of further investigation into the formulation of raloxifene and other medicines as depot preparations, which could prolong the dosing interval and thus improve patient compliance and quality of life.

The Risk Factors of VTE and Survival Prognosis of Patients With Malignant Cancer: Implication for Nursing and Treatment

Venous thromboembolism (VTE) is very common in patients with malignant cancer. We aimed to conduct a retrospective analysis on the risk factors of VTE and its survival prognosis of patients with malignant cancer, to provide evidence into the management of VTE. Patients with malignant cancer treated in our hospital were selected. The characteristic of patients and related lab detection results including activated partial thromboplastin time (APTT), plasma prothrombin time (PT) and thrombin coagulation time (TT), fibrinogen (FIB), thrombin AT-Ⅲ complex (TAT) and D-dimer (D-D) were collected and analyzed. And logistic regression analyses were performed to identify the potential risk factors. And ROC curves were established to evaluate their predictive ability of VTE for patients with malignant cancers. A total of 286 patients were included, of which 63 patients had VTE, the incidence of VTE in patients with malignant cancers was 22.03%. There were significant differences on the D-D, TAT level between VTE and no VTE patients (all P < 0.05). The survival condition of VTE patients was significantly worse than that of no VTE patients(P = 0.017). D-D (RR7.895, 3.228∼19.286) and TAT (6.122, 2.244∼16.695) were risk factors of VTE for patients with cancers (all P < 0.05). The area under the curve (AUC) of D-D, TAT and combined use was 0.764, 0.698, 0.794 respectively, and the cutoff value for D-D, TAT was 1.835mg/L and 4.58μg/L respectively. For cancer patients with D-D >1.835 mg/L and TAT >4.58 μg/L, early interventions are needed for the prophylaxis of VTE.

Sex-specific performance of pre-imaging diagnostic algorithms for pulmonary embolism

Essentials Decision rules for pulmonary embolism are used indiscriminately despite possible sex-differences. Various pre-imaging diagnostic algorithms have been investigated in several prospective studies. When analysed at an individual patient data level the algorithms perform similarly in both sexes. Estrogen use and male sex were associated with a higher prevalence in suspected pulmonary embolism.

SUMMARY

Background In patients suspected of pulmonary embolism (PE), clinical decision rules are combined with D-dimer testing to rule out PE, avoiding the need for imaging in those at low risk. Despite sex differences in several aspects of the disease, including its diagnosis, these algorithms are used indiscriminately in women and men. Objectives To compare the performance, defined as efficiency and failure rate, of three pre-imaging diagnostic algorithms for PE between women and men: the Wells rule with fixed or with age-adjusted D-dimer cut-off, and a recently validated algorithm (YEARS). A secondary aim was to determine the sex-specific prevalence of PE. Methods Individual patient data were obtained from six studies using the Wells rule (fixed D-dimer, n = 5; age adjusted, n = 1) and from one study using the YEARS algorithm. All studies prospectively enrolled consecutive patients with suspected PE. Main outcomes were efficiency (proportion of patients in which the algorithm ruled out PE without imaging) and failure rate (proportion of patients with PE not detected by the algorithm). Outcomes were estimated using (multilevel) logistic regression models. Results The main outcomes showed no sex differences in any of the separate algorithms. With all three, the prevalence of PE was lower in women (OR, 0.66, 0.68 and 0.74). In women, estrogen use, adjusted for age, was associated with lower efficiency and higher prevalence and D-dimer levels. Conclusions The investigated pre-imaging diagnostic algorithms for patients suspected of PE show no sex differences in performance. Male sex and estrogen use are both associated with a higher probability of having the disease.

Back to the future: Hormone replacement therapy as part of a prevention strategy for women at the onset of menopause

In the late 1980s, several observational studies and meta-analyses suggested that hormone replacement therapy (HRT) was beneficial for prevention of osteoporosis, coronary heart disease, dementia and decreased all-cause mortality. In 1992, the American College of Physicians recommended HRT for prevention of coronary disease. In the late 1990s and early 2000s, several randomized trials in older women suggested coronary harm and that the risks, including breast cancer, outweighed any benefit. HRT stopped being prescribed at that time, even for women who had severe symptoms of menopause. Subsequently, reanalyzes of the randomized trial data, using age stratification, as well as newer studies, and meta-analyses have been consistent in showing that younger women, 50-59 years or within 10 years of menopause, have decreased coronary disease and all-cause mortality; and did not have the perceived risks including breast cancer. These newer findings are consistent with the older observational data. It has also been reported that many women who abruptly stopped HRT had more risks, including more osteoporotic fractures. The current data confirm a "timing" hypothesis for benefits and risks of HRT, showing that younger have many benefits and few risks, particularly if therapy is predominantly focused on the estrogen component. We discuss these findings and put into perspective the potential risks of treatment, and suggest that we may have come full circle regarding the use of HRT. In so doing we propose that HRT should be considered as part of a general prevention strategy for women at the onset of menopause.

Mechanisms of hormonal therapy related thrombosis

There is now compelling evidence that use of oral contraceptives and postmenopausal hormonal therapies containing various estrogens is associated with a weak, but clinically relevant risk of both arterial and venous thrombosis. The increased risk is related to type and dose of both estrogen and combined progestagen and mode of delivery. Treatment induces mainly subtle changes in individual components of the coagulation and fibrinolytic systems, but the overall effect is the induction of a prothrombotic phenotype. This brief review summarizes some of the mechanisms responsible the prothrombotic effects of such treatment.

Tissue factor pathway inhibitor polymorphisms in women with and without a history of venous thrombosis and the effects of postmenopausal hormone therapy

Postmenopausal hormone therapy is associated with marked reduction in tissue factor pathway inhibitor (TFPI) levels, and low TFPI levels have been associated with increased risk of venous thrombosis. Polymorphisms in the TFPI gene may affect the expression of TFPI. We aimed to investigate the influences of such polymorphisms on plasma TFPI levels and to investigate the effect of hormone therapy. Four single nucleotide polymorphisms in the TFPI gene (the -287T/C and the -399C/T polymorphisms in the 5' upstream region, and the intron 7 -33T/C and the exon 9 874G/A polymorphisms) were studied with regard to frequency, phenotype, and their influence on hormone therapy in postmenopausal women with a history of venous thrombosis (n = 138), in healthy postmenopausal women (n = 202), and in normal controls (n = 212). The frequencies of the -287C and the -33C variants were nonsignificantly lower in cases than in controls, and the polymorphisms were associated with slightly higher levels of free TFPI antigen (-287C; P = 0.076) and higher TFPI activity (-33C; P < 0.001). The -399T variant showed equal distribution in cases and controls, but was associated with lower levels of TFPI activity (P = 0.036). Conventional-dose hormone therapy induced significant reductions in TFPI levels irrespective of genotypes. In healthy women treated with low-dose hormone therapy, the reduction in TFPI levels was less pronounced with the -287C variant (P = 0.054). Our study indicates that polymorphisms in the TFPI gene may be of importance for plasma TFPI levels and for the effects of hormone therapy.

Tibolone in postmenopausal women: a review based on recent randomised controlled clinical trials

AIM

To critically discuss the use of tibolone (T), in light of a series of very recent double-blind placebo (PL) controlled trials (LISA, LIFT, OPAL, THEBES, LIBERATE) conducted worldwide in a large number of postmenopausal women (PMW).

METHODS

The most relevant publications on T therapy in PMW were considered with emphasis on menopausal symptoms, quality of life, sexuality, bone, cardiovascular system (CVS) and oncologic risk.

RESULTS

T significantly relieves climacteric symptoms and improves mood and sexual well-being (LISA). T is as effective as estrogen-progestin therapy in preventing bone loss and reducing the relative risk of vertebral and non-vertebral fractures (LIFT). By using surrogate endpoints of the individual risks for the CVS, studies show mixed results, but a favourable effect on acute miocardial infarction and thromboembolism has been documented (THEBES, LIFT, OPAL). Although findings about endometrial and colon cancer are reassuring, conclusive data on breast cancer risk with T are not available and an increased risk of recurrence in women with previous breast cancer emerged (LIBERATE).

CONCLUSIONS

T is effective in treating menopausal syndrome with a good tolerability profile. In spite of some unsolved issues in term of safety, T is still a good treatment option for early PMW.

Hormone replacement therapy and the risk of venous thromboembolism: a population-based study

SUMMARY BACKGROUND

Hormone replacement therapy (HRT) using oral estrogen alone or combined with a progestogen is associated with an increased risk of venous thromboembolism (VTE) in postmenopausal women. This risk may differ for tibolone and transdermal HRT.

METHODS

Among the United Kingdom's General Practice Research Database, we identified the cohort of all women aged 50-79 between 1 January 1987 and 1 March 2008. Using a nested case-control approach, all incident cases of VTE occurring during the study period were identified and matched with up to 10 controls selected from the cohort members. Rate ratios (RR) of VTE with current use of tibolone, transdermal and oral HRT were estimated using conditional logistic regression.

RESULTS

The cohort of 955 582 postmenopausal women included 23 505 cases of VTE matched with 231 562 controls. The risk of VTE was not increased with current use of transdermal estrogen alone (RR 1.01; 95% CI, 0.89-1.16) or combined with a progestogen (RR 0.96; 95% CI, 0.77-1.20), or with current use of tibolone (RR 0.92; 95% CI: 0.77-1.10), relative to non-use. On the other hand, the risk was increased with current use of oral estrogen (RR 1.49; 95% CI, 1.37-1.63) and oral estrogen-progestogen (RR 1.54; 95% CI, 1.44-1.65), and increased with estrogen dosage. The risks with oral formulations were particularly elevated during the first year of use but disappeared 4 months after discontinuation.

CONCLUSION

Transdermal HRT and tibolone were not associated with an increased risk of VTE in postmenopausal women.

Postmenopausal Hormone Therapy and Risk of Idiopathic Venous Thromboembolism

Objective— Oral estrogen therapy increases venous thromboembolism risk among postmenopausal women. Although recent data showed transdermal estrogens may be safe with respect to thrombotic risk, the impact of the route of estrogen administration and concomitant progestogens is not fully established.

Methods and Results— We used data from the E3N French prospective cohort of women born between 1925 and 1950 and biennially followed by questionnaires from 1990. Study population consisted of 80 308 postmenopausal women (average follow-up: 10.1 years) including 549 documented idiopathic first venous thromboembolism. Hazard ratios (HR) and 95% confidence intervals (CI) were estimated using Cox proportional models. Compared to never-users, past-users of hormone therapy had no increased thrombotic risk (HR=1.1; 95% CI: 0.8 to 1.5). Oral not transdermal estrogens were associated with increased thrombotic risk (HR=1.7; 95% CI: 1.1 to 2.8 and HR=1.1; 95% CI: 0.8 to 1.8; homogeneity: P =0.01). The thrombotic risk significantly differed by concomitant progestogens type (homogeneity: P <0.01): there was no significant association with progesterone, pregnanes, and nortestosterones (HR=0.9; 95% CI: 0.6 to 1.5, HR=1.3; 95% CI: 0.9 to 2.0 and HR=1.4; 95% CI: 0.7 to 2.4). However, norpregnanes were associated with increased thrombotic risk (HR=1.8; 95% CI: 1.2 to 2.7).

Conclusions— In this large study, we found that route of estrogen administration and concomitant progestogens type are 2 important determinants of thrombotic risk among postmenopausal women using hormone therapy. Transdermal estrogens alone or combined with progesterone might be safe with respect to thrombotic risk.

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.

Performance of five two-sample location tests for skewed distributions with unequal variances

Tests for comparing the locations of two independent populations are associated with different null hypotheses, but results are often interpreted as evidence for or against equality of means or medians. We examine the appropriateness of this practice by investigating the performance of five frequently used tests: the two-sample T test, the Welch U test, the Yuen-Welch test, the Wilcoxon-Mann-Whitney test, and the Brunner-Munzel test. Under combined violations of normality and variance homogeneity, the true significance level and power of the tests depend on a complex interplay of several factors. In a wide ranging simulation study, we consider scenarios differing in skewness, skewness heterogeneity, variance heterogeneity, sample size, and sample size ratio. We find that small differences in distribution properties can alter test performance markedly, thus confounding the effort to present simple test recommendations. Instead, we provide detailed recommendations in Appendix A. The Welch U test is recommended most frequently, but cannot be considered an omnibus test for this problem.

Mechanisms of thrombosis related to hormone therapy

Combined oral contraceptives and combined oral postmenopausal hormone therapy are associated with a weak, but clinically significant risk of arterial and venous thrombosis (VT). The effects are related to dose of estrogen and type of progestin. The main effects are increase in markers of activated coagulation, reduction in coagulation inhibitors, and acquired activated protein C resistance. Reduction in tissue factor pathway inhibitor (TFPI) is probably an important mechanism, which predicts activation of coagulation and acquired resistance to activated protein C. Coagulation markers should be used as intermediate or surrogate markers in early pharmacodynamic studies to evaluate the risk associated with new formulations.

Differential impact of conventional-dose and low-dose postmenopausal hormone therapy, tibolone and raloxifene on C-reactive protein and other inflammatory markers

BACKGROUND

Postmenopausal hormone therapy (HT) is associated with an increased risk for arterial and venous thrombosis.

OBJECTIVES

To compare the impact of HT, tibolone, and raloxifene on C-reactive protein (CRP) and other inflammatory markers, and to investigate possible underlying mechanisms for changes in CRP and D-dimer.

METHODS

Two hundred and two healthy women were randomly assigned to treatment for 12 weeks with either low-dose HT containing 1 mg of 17beta-estradiol and 0.5 mg of norethisterone acetate (NETA) (n = 50), conventional-dose HT containing 2 mg of 17beta-estradiol and 1 mg of NETA (n = 50), 2.5 mg of tibolone (n = 51), or 60 mg of raloxifene (n = 51).

RESULTS

CRP increased in the conventional-dose HT and low-dose HT groups. These changes were significantly more pronounced in the conventional-dose HT group (RMANOVA, P = 0.02). Also, tibolone was associated with an increase in CRP, in contrast to raloxifene, which reduced CRP. Reductions in levels of Lp(a), intercellular adhesion molecule-1 (ICAM-1), P-selectin, E-selectin, monocyte chemotactic protein 1 (MCP-1) and interleukin-6 (IL-6) were observed in all treatment groups. The changes were most pronounced for the conventional-dose HT group, and least pronounced for the raloxifene group, whereas the changes in those allocated to tibolone and low-dose HT were intermediary. Increased levels of tumor necrosis factor (TNF)-alpha and von Willebrand factor (VWF) were seen in the raloxifene group. We observed positive associations between changes in IL-6, VWF, MCP-1, and CRP.

CONCLUSIONS

The regimens had markedly different impacts on markers of inflammation. The average increase in CRP was not accompanied by increases in the average levels of IL-6, TNF-alpha or other markers, but women with large reductions in IL-6 had reduced increases in CRP.

Hormone therapy and raloxifene reduce the coagulation inhibitor potential

The coagulation inhibitor potential (CIP) assay may detect major thrombophilia at a sensitivity of 100% and a specificity of 70-80%. Subnormal CIP might be associated with increased risk of thrombosis. This study compared the effect on CIP in plasma samples from postmenopausal women treated with four different regimens. Fibrin aggregation in plasma was monitored after activation with tissue factor. The effect of potentiated inhibition of coagulation was measured. Plasma samples from 202 healthy women randomly assigned to receive treatment for 12 weeks with conventional-dose or low-dose hormone therapy, raloxifene or tibolone were examined. Major thrombophilias were excluded. Compared with baseline, the median level in CIP was reduced by 64% in the conventional-dose group, by 38% in the low-dose group and by 31% in the raloxifene group, whereas for those treated with tibolone the median CIP increased by 9%. The median changes in CIP were significant for both hormone therapy groups (P < 0.0001) and for the raloxifene group (P = 0.003), but not for the tibolone group (P = 0.653). The 12 women with heterozygous factor V Leiden mutation had a significantly reduced median CIP level (P < 0.0001) at baseline. Hormone therapy and raloxifene, associated with venous thromboembolism, reduce the CIP. Tibolone does not reduce the CIP.

Cardiovascular Effects of Tibolone: A Selective Tissue Estrogenic Activity Regulator

Traditionally, it was accepted that long-term hormone replacement therapy (HRT) has a cardiovascular beneficial effect in postmenopausal women with and without coronary artery disease (CAD). However, randomized trials in postmenopausal women have not shown any benefit in either primary or secondary prevention of cardiovascular events. Therefore, these findings have raised the question of whether traditional HRT (i.e., estrogen and progesterone) has a cardioprotective effect in women at risk for or with established CAD. Concerns about the use of conventional HRT have led to a search for alternatives. Tibolone is a synthetic compound with estrogenic, androgenic, and progestogenic properties that relieves climacteric symptoms and prevents postmenopausal bone loss. Tibolone possesses a tissue-selective mechanism of action that differs from that of estrogen and/or progestogen. Unlike these compounds, tibolone's metabolites play a central role in its mode of action. Tibolone is widely used for HRT. However, its clinical impact on cardiovascular disease is still under study. The current review focuses on the effects of tibolone on the cardiovascular system and discusses clinical investigations with this compound in postmenopausal women.

Differential effects of conventional and low dose oral hormone therapy (HT), tibolone, and raloxifene on coagulation and fibrinolysis

INTRODUCTION

We have recently reported that different hormone regimens given to healthy post-menopausal women had markedly different effects on activation of coagulation. Low-dose hormone therapy (HT) and raloxifene, as opposed to conventional-dose HT and tibolone, were associated with no or minor activation of coagulation. The aim of this study was to elucidate the mechanism(s) for differences in coagulation activation by analysing clotting and fibrinolytic factors and coagulation inhibitors.

MATERIALS AND METHODS

202 healthy women were randomly assigned to receive treatment for 12 weeks with either low dose HT containing 1 mg 17 beta-estradiol+0.5 mg norethisterone acetate (NETA) (n=50), conventional dose HT containing 2 mg 17 beta-estradiol and 1 mg NETA (n=50), 2.5 mg tibolone (n=51), or 60 mg raloxifene (n=51) in an open-label design.

RESULTS

The conventional-and low-dose HT groups generally showed similar effects, i.e., reductions in both clotting factors and inhibitors, but the effects were markedly more pronounced in the conventional-dose HT group. Compared with the low-dose HT group those treated with tibolone showed more pronounced decreases in factor VII, less reduction of antithrombin and protein C and even increased levels in protein S and tissue factor pathway inhibitor. As opposed to the low-dose HT group the reductions in inhibitors in the raloxifene group were smaller. Moreover in those allocated to raloxifene reduced levels of fibrinogen were seen.

CONCLUSIONS

Our study demonstrates that the different HT regimens and raloxifene exert differential effects on coagulation factors, inhibitors and fibrinolytic factors.