A 3-year study of prevention of postmenopausal bone loss: conjugated equine estrogens plus medroxyprogesterone acetate versus tibolone

Effect of Tibolone on Bone Mineral Density in Postmenopausal Women: Systematic Review and Meta-Analysis

Low bone mineral density (BMD) on postmenopausal women causes bone fragility and fracture risk. Tibolone seems to prevent bone loss. Therefore, this systematic review with meta-analysis synthesizes the tibolone effect on BMD percent change in lumbar spine (LS), femoral neck (FN), and total hip (TH) in postmenopausal women. Controlled trials that provided tibolone evidence on the efficacy of tibolone in preventing loss of BMD were included. Regarding the included studies, a pooled mean difference (MD) with 95% confidence intervals (95%CI) was estimated to determine the BMD percentage change. Eleven studies were identified and eight were included in the quantitative analysis. Tibolone at a dose of 2.5 mg increased BMD compared with non-active controls at 24 months in LS (MD 4.87%, 95%CI: 4.16-5.57, and MD 7.35%, 95%CI: 2.68-12.01); and FN (MD 4.85%, 95%CI: 1.55-8.15, and 4.21%, 95%CI: 2.99-5.42), with Hologic and Lunar scanners, respectively. No difference was observed when tibolone 2.5 mg dose was compared with estrogen therapy (ET) at 24 months, LS (MD -0.58%, 95%CI: -3.77-2.60), FN (MD -0.29%, 95%CI: -1.37-0.79), and TH (MD -0.12%, 95%CI: -2.28-2.53). Therefore, tibolone increases BMD in LS and FN compared to non-active controls, and there was no showed difference with ET.

Management of age-related osteoporosis and prevention of associated fractures

Osteoporosis and related fractures are a significant concern for the global community. As the population continues to age, morbidity and mortality from fractures due to low bone mineral density (BMD) will likely continue to increase. Efforts should be made to screen those at risk for osteoporosis, identify and address various risk factors for falls and associated fractures, ensure adequate calcium and vitamin D intake, and institute pharmacological therapy to increase BMD when indicated. Agents which increase BMD and have been shown to decrease fractures, particularly at the hip, should be considered preferentially over those for which only BMD data are available. Drugs which have been shown to decrease the risk of age-related osteoporotic fractures include oral bisphosphonates (alendronate, ibandronate, and risedronate), intranasal calcitonin, estrogen receptor stimulators (eg, estrogen, selective estrogen receptor modulators [raloxifene]), parathyroid hormone (teriparatide), sodium fluoride, and strontium ranelate. Data are beginning to emerge supporting various combination therapies (eg, bisphosphonate plus an estrogen receptor stimulator), though more data are needed to identify combinations which are most effective and confer added fracture protection. In addition, further research is needed to identify ideal regimens in special populations such as nursing home patients and men.

Effects of tibolone and raloxifene on bone mineral density in osteopenic postmenopausal women

A randomized trial was conducted in osteopenic postmenopausal women to compare the efficacy of tibolone versus raloxifene on BMD of the lumbar spine and hip. Tibolone increased lumbar spine and total hip BMD to a statistically significantly greater extent than raloxifene after two years of treatment.

INTRODUCTION

Both tibolone, a selective tissue estrogenic activity regulator (STEAR), and raloxifene, a selective estrogen receptor modulator (SERM), are known to prevent postmenopausal bone loss. However, no head-to-head studies to compare the efficacy on bone have been performed.

METHODS

A double-blind, randomized trial was conducted in osteopenic postmenopausal women aged 60-79 years to compare the effects of tibolone 1.25 mg/day to raloxifene 60 mg/day on bone mineral density (BMD). Serum osteocalcin and serum type I collagen C-telopeptides were measured as biochemical markers of bone metabolism.

RESULTS

Three hundred and eight subjects were allocated to treatment. Both treatments significantly increased lumbar spine BMD, however the increase was significantly larger after tibolone treatment than after raloxifene treatment (at year 1: 2.2% versus 1.2%, p<0.01 and at year 2: 3.8% versus 2.1%, p<0.001). After 2 years of treatment, the increase in total hip BMD in the tibolone group was significantly larger than in the raloxifene group (p<0.05). Both treatments significantly reduced type I collagen C-telopeptides and osteocalcin levels when compared to baseline.

CONCLUSIONS

Tibolone 1.25 mg/day for 2 years prevents postmenopausal bone loss in older women and results in a larger increase of BMD both at the lumbar spine and hip than raloxifene.

Prevention and treatment of postmenopausal osteoporosis

Osteoporosis is a systemic disease characterized by low bone mass and microarchitectural deterioration of the skeleton leading to enhanced bone fragility and an increased risk of fracture. Prior to fracture, diagnosis is established by documenting low bone mass. In the first section of this article we review the clinical use of bone mass measurements and biochemical markers of bone remodeling in selecting patients most in need of preventive therapy at menopause. Women with high bone turnover lose bone at menopause more rapidly than those with normal bone turnover and are more likely to derive benefit from the several preventive therapies available. The second section addresses the available technologies used to diagnose osteoporosis and/or establish fragility fracture risk using noninvasive bone mass measurement and biochemical markers of bone remodeling separately or in combination. In the third section we review the several treatment options available for patients with osteoporosis, including alendronate (alendronic acid), risendronate (risedronic acid), calcitonin, teriparatide, and raloxifene, and the approaches to monitoring the therapeutic response. The final section deals with fall protection--an often forgotten aspect of management of the patient at risk for sustaining and osteoporotic fragility fracture.

The influence of 5-year therapy with tibolone on the lipid profile in postmenopausal women with mild hypercholesterolemia

Our objective was to investigate the effects of 5-year therapy with tibolone on the lipid profile in postmenopausal women with mild hypercholesterolemia (total cholesterol, 241 +/- 7 mg/dl; LDL cholesterol, 153 +/- 9 mg/dl). Eighty-two patients were divided into two groups. Group A (53 women) received 2.5 mg of tibolone per day. Group B (29 women) received no tibolone. Total, low- and high-density lipoprotein cholesterol and lipoprotein(a) were found to be decreased in the tibolone group, by 17.7%, 32%, 15.5% and 12%, respectively (p < 0.01) throughout the 5-year treatment, while triglycerides showed no significant change. The lipid profile in the control group remained at its initial values. Menopausal symptoms disappeared in the treatment group within the first 5 months, whereas they deteriorated in the control group during the first 2 years. Although a few unwanted side-effects on hormone-dependent tissues were observed (including vaginal spotting in 11.3% and febrile hemorrhagic cystic mastopathy in 3.8%) long-term therapy with tibolone seemed to be well tolerated, and appeared to have a beneficial effect on the levels of serum lipids.

The effect of tibolone on bone mineral density in postmenopausal women with osteopenia or osteoporosis—8 years follow-up

OBJECTIVES

This longitudinal observational study evaluated the effect of 8 years of uninterrupted treatment of tibolone on bone mineral density (BMD) in postmenopausal women with significant osteopenia or osteoporosis.

MATERIAL AND METHODS

Subjects were 66 postmenopausal women (29 with moderate or severe osteopenia and 37 with osteoporosis) who took tibolone (2.5 mg nocte) uninterruptedly for over 8 years and who attended for annual BMD assessments. Their mean age was 66.7 (0.86) years (range 50-86 years). BMD measurements at the lumbar spine and proximal femur were performed annually by dual-energy X-ray absorptiometry (DEXA).

RESULTS

During the 8 years of treatment with tibolone there was a significant increase in BMD at the spine (P < 0.001) and at the hip (P < 0.001). Women who did not have previous oestrogen therapy had significantly greater response to tibolone than those who had previous treatment with conventional hormone replacement therapy (HRT).

CONCLUSION

This long-term observational study provides evidence of the effectiveness of tibolone in postmenopausal women with moderate/severe osteopenia and osteoporosis in terms of a significant increase in BMD.

Pros and cons of existing treatment modalities in osteoporosis: a comparison between tibolone, SERMs and estrogen (+/-progestogen) treatments

Tibolone, selective estrogen receptor modulators (SERMs) like tamoxifen and raloxifene, and estrogen (+/-progestogen) treatments prevent bone loss in postmenopausal women. They exert their effects on bone via the estrogen receptor (ER) and the increase in bone mass is due to resorption inhibition. The effect of SERMs on bone mineral density is less than that with the other treatments, but the SERM raloxifene still has a positive effect on vertebral fractures. In contrast to tibolone and estrogens (+/-progestogen), SERMs do not treat climacteric complaints, whilst estrogen plus progestogen treatments cause a high incidence of bleeding. Estrogen plus progestogen combinations have compromising effects on the breast. Tibolone and SERMs do not stimulate the breast or endometrium. Unlike SERMs, tibolone does not possess antagonistic biological effects via the ER in these tissues. Estrogenic stimulation in these tissues is prevented by local metabolism and inhibition of steroid metabolizing enzymes by tibolone and its metabolites. SERMs and estrogen (+/-progestogen) treatments increase the risk of venous thromboembolism (VTE), whilst estrogen (+/-progestogen) combinations have unwanted effects on cardiovascular events. So far, no detrimental effects of tibolone have been observed with respect to VTE or cardiovascular events. The clinical profile of tibolone therefore has advantages over those of other treatment modalities. It is also clear that tibolone is a unique compound with a specific mode of action and that it belongs to a separate class of compounds that can best be described as selective, tissue estrogenic activity regulators (STEARs).

What factors account for hormone replacement therapy prescribing frequency?

OBJECTIVES

The purpose of this study was to compare hormone replacement therapy (HRT) prescribing frequency to provider characteristics, attitudes and beliefs about menopause and HRT.

METHODS

There was a mailed survey of providers at a large staff-model HMO in Washington state. Participants included 250 family practice physicians, 22 gynecologists, and 13 women's health care specialists and nurse midwives (83% response rate). The primary outcome, "HRT prescribing frequency" (derived from automated pharmacy and visit data) was defined as: the total number of estrogen prescriptions written by the provider and filled by women aged 50-80 years during the 12 months prior to the survey, divided by the number of visits made to the provider by women aged 50-80 years during that same 12-month period. Covariates included provider characteristics and beliefs about menopause and HRT. Logistic regression was used to distinguish providers in the upper 40% versus the lower 60% of HRT prescribing frequency.

RESULTS

Controlling for age and practice type, HRT prescribing frequency was lower among men than women providers (odds ratio [OR] 0.38, 95% confidence interval [CI] 0.21-0.65), higher among providers who agreed (vs. disagreed or neutral) that a convincing scientific case has been made that HRT prevents heart disease (OR 2.66, 95% CI 1.53-4.61), and higher among those in the upper tertile vs. lower tertiles of an HRT encouragement scale (OR 2.50, 95% CI 1.29-4.85).

CONCLUSIONS

Female providers and providers with positive attitudes toward HRT are the most likely to prescribe it.

Double-blind, placebo-controlled study of the effects of tibolone on bone mineral density in postmenopausal osteoporotic women with and without previous fractures

A 2-year placebo-controlled, randomized, two-center prospective study was carried out to assess the effects of tibolone (Org OD14, Livial) on trabecular and cortical bone mass and bone biochemistry parameters in elderly postmenopausal women with and without previous fractures. In total, 107 subjects, 71 with fractures and 36 without fractures, were randomized to tibolone (n = 64) or placebo (n = 43). Their mean age was 63.1 years. Bone mineral density (BMD) (g/cm2) was assessed at baseline and every 6 months for 2 years by dual-energy X-ray absorptiometry (DXA). Mean baseline values were 0.79 and 0.80 for the lumbar spine in the tibolone and placebo groups, respectively, and for the femoral neck 0.64 in both groups. Serum and urinary bone biochemistry parameters were measured concurrently. An analysis of variance (ANOVA) model including center and group was applied. The completers' group was the primary subset for the analysis; the intention-to-treat (ITT) group was also analyzed. Results are expressed as the percentage change at 24 months and the annual rate of change percentage year. The tibolone group showed an overall mean increase (vs. placebo) in BMD at the lumbar spine of 7.2% (p < 0.001) and for the femoral neck 2.6% (p < 0.001). In subjects with previous fractures increases were 6.0% and 4.0% for the lumbar spine and femoral neck, while in those with no fractures, respective changes were 8.9% and 1.1%. Overall changes in the placebo group were 0.9% and -1.6% for the lumbar spine and femoral neck, respectively. A significant fall in bone biochemistry parameters showed that tibolone inhibits osteoclastic activity. In conclusion we have found that tibolone 2.5 mg induces significant increases of trabecular and cortical bone mass in elderly postmenopausal osteoporotic women with and without previous fractures.