Administration of tibolone decreases 24h heart rate but not blood pressure of post-menopausal women

Does tibolone treatment have favorable effects on obesity, blood pressure, and inflammation? A meta-analysis of randomized controlled trials

The clinical effects of tibolone on cardiometabolic markers are an underlying question in postmenopausal women. We aimed to meta-analyze the effects of tibolone on anthropometric indicators of obesity, blood pressure (BP), and on C-reactive protein (CRP) levels in postmenopausal women. Two independent reviewers searched Scopus, Web of Science, PubMed/Medline, and Embase up to until 20 April 2021. Weighted mean differences (WMDs) and 95% confidence interval (CI) were calculated through the DerSimonian and Laird random-effect models between the tibolone and the control groups. Data from 20 eligible included showed that tibolone treatment increased the body mass index (BMI) by 0.23 kg/m² (95% CI: 0.017 to 0.45, p = 0.03) but did not significantly increase body weight (WMD: 1.128 kg, 95% CI: -1.76 to 4.02, p = 0.44) or waist circumference (WC) (WMD: 0.64 cm, 95% CI: -3.18 to 4.48, p = 0.74). Also, tibolone treatment neither changed the systolic BP (WMD: 2.60 mmHg, 95% CI: -2.52 to 7.72, p = 0.31) nor the diastolic BP (WMD: 0.711 mmHg, 95% CI: -2.52 to 3.94, p = 0.66), but increased CRP levels by 0.44 mg/L (95% CI: 0.10 to 0.78, p = 0.01). Tibolone treatment administered in postmenopausal women increased BMI and CRP but did not change body weight, WC, and SBP. Diastolic BP decreased after the tibolone intervention only in the studies lasting 26 weeks versus ˃26 weeks.

Short-term and long-term effects of tibolone in postmenopausal women

BACKGROUND

Tibolone is a synthetic steroid used for the treatment of menopausal symptoms, on the basis of short-term data suggesting its efficacy. We considered the balance between the benefits and risks of tibolone.

OBJECTIVES

To evaluate the effectiveness and safety of tibolone for treatment of postmenopausal and perimenopausal women.

SEARCH METHODS

In October 2015, we searched the Gynaecology and Fertility Group (CGF) Specialised Register, the Cochrane Central Register of Controlled Trials (CENTRAL), MEDLINE, Embase and PsycINFO (from inception), the Cumulative Index to Nursing and Allied Health Literature (CINAHL) and clinicaltrials.gov. We checked the reference lists in articles retrieved.

SELECTION CRITERIA

We included randomised controlled trials (RCTs) comparing tibolone versus placebo, oestrogens and/or combined hormone therapy (HT) in postmenopausal and perimenopausal women.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures of The Cochrane Collaboration. Primary outcomes were vasomotor symptoms, unscheduled vaginal bleeding and long-term adverse events. We evaluated safety outcomes and bleeding in studies including women either with or without menopausal symptoms.

MAIN RESULTS

We included 46 RCTs (19,976 women). Most RCTs evaluated tibolone for treating menopausal vasomotor symptoms. Some had other objectives, such as assessment of bleeding patterns, endometrial safety, bone health, sexuality and safety in women with a history of breast cancer. Two included women with uterine leiomyoma or lupus erythematosus. Tibolone versus placebo Vasomotor symptomsTibolone was more effective than placebo (standard mean difference (SMD) -0.99, 95% confidence interval (CI) -1.10 to -0.89; seven RCTs; 1657 women; moderate-quality evidence), but removing trials at high risk of attrition bias attenuated this effect (SMD -0.61, 95% CI -0.73 to -0.49; odds ratio (OR) 0.33, 85% CI 0.27 to 0.41). This suggests that if 67% of women taking placebo experience vasomotor symptoms, between 35% and 45% of women taking tibolone will do so. Unscheduled bleedingTibolone was associated with greater likelihood of bleeding (OR 2.79, 95% CI 2.10 to 3.70; nine RCTs; 7814 women; I2 = 43%; moderate-quality evidence). This suggests that if 18% of women taking placebo experience unscheduled bleeding, between 31% and 44% of women taking tibolone will do so. Long-term adverse eventsMost of the studies reporting these outcomes provided follow-up of two to three years (range three months to three years). Breast cancerWe found no evidence of differences between groups among women with no history of breast cancer (OR 0.52, 95% CI 0.21 to 1.25; four RCTs; 5500 women; I2= 17%; very low-quality evidence). Among women with a history of breast cancer, tibolone was associated with increased risk (OR 1.5, 95% CI 1.21 to 1.85; two RCTs; 3165 women; moderate-quality evidence). Cerebrovascular eventsWe found no conclusive evidence of differences between groups in cerebrovascular events (OR 1.74, 95% CI 0.99 to 3.04; four RCTs; 7930 women; I2 = 0%; very low-quality evidence). We obtained most data from a single RCT (n = 4506) of osteoporotic women aged 60 to 85 years, which was stopped prematurely for increased risk of stroke. Other outcomesEvidence on other outcomes was of low or very low quality, with no clear evidence of any differences between the groups. Effect estimates were as follows:• Endometrial cancer: OR 2.04, 95% CI 0.79 to 5.24; nine RCTs; 8504 women; I2 = 0%.• Cardiovascular events: OR 1.38, 95% CI 0.84 to 2.27; four RCTs; 8401 women; I2 = 0%.• Venous thromboembolic events: OR 0.85, 95% CI 0.37 to 1.97; 9176 women; I2 = 0%.• Mortality from any cause: OR 1.06, 95% CI 0.79 to 1.41; four RCTs; 8242 women; I2 = 0%. Tibolone versus combined HT Vasomotor symptomsCombined HT was more effective than tibolone (SMD 0.17, 95% CI 0.06 to 0.28; OR 1.36, 95% CI 1.11 to 1.66; nine studies; 1336 women; moderate-quality evidence). This result was robust to a sensitivity analysis that excluded trials with high risk of attrition bias, suggesting a slightly greater disadvantage of tibolone (SMD 0.25, 95% CI 0.09 to 0.41; OR 1.57, 95% CI 1.18 to 2.10). This suggests that if 7% of women taking combined HT experience vasomotor symptoms, between 8% and 14% of women taking tibolone will do so. Unscheduled bleedingTibolone was associated with a lower rate of bleeding (OR 0.32, 95% CI 0.24 to 0.41; 16 RCTs; 6438 women; I2 = 72%; moderate-quality evidence). This suggests that if 47% of women taking combined HT experience unscheduled bleeding, between 18% and 27% of women taking tibolone will do so. Long-term adverse eventsMost studies reporting these outcomes provided follow-up of two to three years (range three months to three years). Evidence was of very low quality, with no clear evidence of any differences between the groups. Effect estimates were as follows:• Endometrial cancer: OR 1.47, 95% CI 0.23 to 9.33; five RCTs; 3689 women; I2 = 0%.• Breast cancer: OR 1.69, 95% CI 0.78 to 3.67; five RCTs; 4835 women; I2 = 0%.• Venous thromboembolic events: OR 0.44, 95% CI 0.09 to 2.14; four RCTs; 4529 women; I2 = 0%.• Cardiovascular events: OR 0.63, 95% CI 0.24 to 1.66; two RCTs; 3794 women; I2 = 0%.• Cerebrovascular events: OR 0.76, 95% CI 0.16 to 3.66; four RCTs; 4562 women; I2 = 0%.• Mortality from any cause: only one event reported (two RCTs; 970 women).

AUTHORS' CONCLUSIONS

Moderate-quality evidence suggests that tibolone is more effective than placebo but less effective than HT in reducing menopausal vasomotor symptoms, and that tibolone is associated with a higher rate of unscheduled bleeding than placebo but with a lower rate than HT.Compared with placebo, tibolone increases recurrent breast cancer rates in women with a history of breast cancer, and may increase stroke rates in women over 60 years of age. No evidence indicates that tibolone increases the risk of other long-term adverse events, or that it differs from HT with respect to long-term safety.Much of the evidence was of low or very low quality. Limitations included high risk of bias and imprecision. Most studies were financed by drug manufacturers or failed to disclose their funding source.

Short and long term effects of tibolone in postmenopausal women

BACKGROUND

Tibolone is an option available for the treatment of menopausal symptoms, based on short-term data on its efficacy. However, there is a need to consider the balance between the benefits and risks of tibolone as there are concerns about breast and endometrial cancer as well as stroke.

OBJECTIVES

To evaluate the effectiveness and safety of tibolone in treating postmenopausal women.

SEARCH METHODS

We searched the Cochrane Menstrual Disorders and Subfertility Group (MDSG) Specialised Register (19 April 2011), Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library 2011, 2nd Quarter), MEDLINE (from inception to 19 April 2011), EMBASE (1980 to week 3 April 2011), PsycINFO (1806 to week 3 April 2011), Clinical Trials.gov (30 April 2011). Individual researchers and the current manufacturer of tibolone were contacted to identify unpublished and ongoing trials.

SELECTION CRITERIA

Randomised controlled trials (RCTs) that compared tibolone versus placebo, estrogens or combined hormone replacement therapy (HT) by assessing the percentage of women with menopausal symptoms, the severity of those symptoms and the occurrence of safety outcomes in postmenopausal women.

DATA COLLECTION AND ANALYSIS

Four review authors independently extracted information from the articles, resolving discrepancies by consensus. All outcomes studied were dichotomous. Odds ratios (OR) and 95% confidence intervals (CI) were calculated using the random-effects model. Heterogeneity of studies was taken into account before deciding to combine the data.

MAIN RESULTS

When compared to placebo, tibolone was more effective in relieving the frequency of vasomotor symptoms (two RCTs, n = 847; OR 0.42, 95% CI 0.25 to 0.69), although only the 2.5 mg/day dose of tibolone was significantly better than placebo; but with increased vaginal bleeding (seven RCTs, n = 7462; OR 2.75, 95% CI 1.99 to 3.80). When compared to equipotent doses of combined HT, tibolone reduced vaginal bleeding (15 RCTs, n = 6342; OR 0.32, 95% CI 0.24 to 0.42) but was less effective in relieving the frequency of vasomotor symptoms (two RCTs, n = 545; OR 4.16, 95% CI 1.50 to 11.58).As for long term safety, two major RCTs of tibolone versus placebo provided the most relevant data. An RCT of 3098 women with breast cancer and menopausal symptoms was halted after 3.1 years because of increased tumour recurrence (OR 1.50; 95% CI 1.21 to 1.85). However, in another RCT that selected osteoporotic women with negative mammograms (n = 4506) tibolone was associated with a reduction in breast cancer compared to placebo after 2.8 years (OR 0.32, 95% CI 0.13 to 0.79) although the trial was not specifically designed to assess that outcome and the number of overall events was low. In the same RCT, an excess risk of stroke was observed (OR 2.18, 95% CI 1.12 to 4.21). There was no clear evidence of a tibolone effect on endometrial cancer compared with placebo given the low number of events (seven RCTs, n = 8152; OR 1.98, 95% CI 0.73 to 5.32).There was no evidence of a difference in long term safety between tibolone and combined HT.

AUTHORS' CONCLUSIONS

Tibolone, used at the daily dose of 2.5 mg, may be less effective than combined HT in alleviating menopausal symptoms although it reduced the incidence of vaginal bleeding. There was evidence that treatment with combined HT was more effective in managing menopausal symptoms than was tibolone. Available data on the long term safety of tibolone is concerning given the increase in the risk of breast cancer in women who had already suffered from breast cancer in the past and in a separate trial the increase in the risk of stroke in women whose mean age was over 60 years. Similar concerns may exist for estroprogestins but their overall benefit-risk profile is better known and is more directly related to women with menopausal symptoms.

Effects of menopause and tibolone on different cardiovascular biomarkers in healthy women

BACKGROUND AND AIM

The effects of tibolone on cardiovascular risk is not yet fully understood today. We designed this study to assess the effect of the menopausal status and tibolone treatment (2.5 mg/day for 3 months) on different biomarkers of cardiovascular risk in healthy women.

METHODS

Blood arterial pressure were measured, and blood samples collected for glucose, lipid profile (total cholesterol, high density lipoproteins, HDL, low density lipoproteins, and triglycerides), inflammatory (C-reactive protein, Interleukin-6, IL-6, tumor necrosis factor alpha, TNF alpha) and oxidative stress (hydroperoxides and antioxidant capacity) evaluation in 15 premenopausal (mean age: 30 +/- 4 years) and 15 postmenopausal (mean age: 52 +/- 3, mean time from menopause 1.4 +/- 0.4 years) women before and after tibolone treatment.

RESULTS

The menopausal status is associated with increased systolic and diastolic pressure (p<0.05), higher IL-6 (p<0.05) and TNF alpha (p<0.01), and lower antioxidants (p<0.01). However, blood pressure (p<0.05), glucose (p<0.05), TNF alpha (p<0.05) and HDL (p<0.05) fell after tibolone, which did not significantly affect levels of the other biochemical parameters.

CONCLUSIONS

As menopause is associated with increased blood pressure, inflammation and oxidative stress, tibolone restores blood pressure and has beneficial effect on inflammation and glycemia without worsening oxidative stress, although it also reduces HDL levels. Such modifications should be taken into account when tailoring menopausal therapies to specific requirements of each woman.

Individual differences in equol production capability modulate blood pressure in tibolone-treated postmenopausal women: lack of effect of soy supplementation

OBJECTIVES

Equol, a gut bacterial metabolite of the isoflavone daidzein, has been associated with beneficial health effects. Recent studies indicate that women with intestinal capacity to convert daidzein to equol also have the capacity to alter steroid metabolism and bioavailability of estrogens.

METHODS

We evaluated whether individual equol production capability, while not consuming soy supplement, was associated with lower blood pressure in postmenopausal women using tibolone. In addition, in a randomized, placebo-controlled, cross-over trial we assessed the effect of soy supplementation on blood pressure in both equol-producing (n = 20) and non-equol-producing (n = 20) women using tibolone. Blood pressure was recorded with a validated oscillometric technique.

RESULTS

The circulating equol levels rose 20-fold in the equol producers and 1.9-fold in the non-equol producers. At baseline, systolic blood pressure (129.9 +/- 2.6 vs. 138.5 +/- 3.1 mmHg, p = 0.02), diastolic blood pressure (72.2 +/- 1.5 vs. 76.6 +/- 1.3 mmHg, p = 0.01) and mean arterial blood pressure (93.5 +/- 1.7 vs. 99.9 +/- 1.8 mmHg, p = 0.007) were lower in equol producers compared to non-equol producers. Soy supplementation had no effect on blood pressure in either group, whereas the baseline differences persisted.

CONCLUSIONS

Postmenopausal women using tibolone characterized as equol producers had lower blood pressure compared to non-equol producers. Soy supplementation for 2 months had no blood pressure-lowering effect.

Effects of hormone replacement therapy type and route of administration on plasma matrix metalloproteinases and their tissue inhibitors in postmenopausal women

BACKGROUND

Matrix metalloproteinases (MMPs) are implicated in numerous disease states including cardiovascular disease and cancer. Because recent studies have shown a detrimental effect of hormone replacement therapy on cardiovascular disease and breast cancer, we investigated whether there are any differences in the concentrations of MMPs and their tissue inhibitors (TIMPs) in women receiving various forms of postmenopausal therapy.

MATERIAL AND METHODS

A total of 195 healthy postmenopausal women were assessed: 46 were taking tibolone, 47 were taking transdermal estradiol, 46 were taking conjugated equine estrogens (CEE), and 56 were not taking any menopausal therapy (CTR). Plasma levels of MMP-2 and -9 and TIMP-1 and TIMP-2 were measured by ELISA methods.

RESULTS

MMP-9 levels were significantly higher in the CEE group in comparison with healthy women not receiving menopausal therapy (P < 0.05). In contrast, MMP-9 levels in the tibolone group were significantly lower than in any other group (P < 0.01, compared with transdermal estradiol and CTR, and P < 0.001, compared with CEE). MMP-9 to TIMP-1 ratio was also significantly higher in the CEE, compared with CTR (P < 0.05), and lower in the tibolone group (P < 0.01, compared with all groups). MMP-2 levels were higher in the CEE group, compared with healthy women not receiving any menopausal therapy, and women taking tibolone (P < 0.05).

CONCLUSIONS

Our study demonstrates differential effects of various forms of postmenopausal therapy on serum levels of MMP-9 and MMP-2. It remains to be established whether these differences might be associated with differences in risks of cardiovascular disease and cancer in these women.