Combined therapy with estrogen and etidronate has an additive effect on bone mineral density in the hip and vertebrae: four-year randomized study

Recurrence of vertebral fracture with cyclical etidronate therapy in osteoporosis: histomorphometry and X-Ray microanalysis evaluation

In an open prospective study, we evaluated differences between patients with (wRVF group) and without recurrence of vertebral fracture (woRVF group) during cyclical etidronate therapy for osteoporosis. Thirty-two patients (age 64 +/- 1.8 years) characterized by at least one osteoporotic VF were treated during 1 year. At baseline, body mass index was significantly lower (23.3 +/- 0.6 vs. 26.9 +/- 1.0 kg/m2, p< 0.05), the number of previous VFs was higher (4.0 +/- 0. 4 vs. 2.4 +/- 0.4, NS), and patients were older in the wRVF group as compared with the woRVF group (67.8 +/- 3 vs. 62.6+/- 2.2 year, NS). Trabecular bone volume (11.6 +/- 1.2 vs. 15 +/- 0.9%, p< 0.05) and trabecular number (1.06 +/- 0.08 vs. 1.27 +/- 0.05, p < 0.05) were significantly lower in the wRVF group. None of the baseline resorptive variables differed, whereas the bone formation rate (BFR) was 2-fold lower in the wRVF group (p< 0. 05). After 1 year of treatment, osteoclast number, active eroded surfaces, and resorption depth dramatically decreased in both groups (p< 0. 01). To a lesser extent, the mineral apposition rate and serum alkaline phosphatase level were significantly reduced (p< 0.05). No impaired mineralization was observed. Using X-ray microanalysis, we found no abnormality in bone mineral but a significant increase of the calcium/phosphorus ratio during treatment in the wRVF group. Our results demonstrate that recurrence of VFs within the first year of cyclical etidronate therapy was related neither to a lack of histologic response to the treatment nor induction of an abnormality of mineralization. VFs were more likely in the presence of a decreased BFR and lower trabecular connectivity, providing support for treating osteoporotic patients with etidronate early in the course of the disease.

Prevention and treatment of osteoporosis in the elderly

Due to age-associated bone losses, all elderly are prone to osteoporosis, which often leads to fractures. Fractures frequently result in dependency and institutionalization, as well as physical deformities that may lead to respiratory and cardiovascular problems. Currently, no drugs exist to promote new bone formation. Thus care of the elderly focuses primarily on lifestyle modification and increased dietary intake of calcium and vitamin D; decreased intake of caffeine, phosphates, and alcohol; smoking cessation; increased exercise; and drugs. Drugs for preventing osteoporosis include supplemental calcium and vitamin D, hormone replacement therapy, and alendronate. Drugs that enhance bone loss or increase the likelihood of falls should be eliminated, if possible, or the dosages adjusted. Making residences safer will also help to minimize the potential for falls. Drugs for treating osteoporosis include hormone replacement therapy, alendronate, and nasal calcitonin. The prevention and treatment plan is individualized for each patient, taking into account personal preferences, risk factors for osteoporosis and fracture, concomitant diseases and drug therapies, efficacy and tolerance of osteoporosis therapy, quality of life, life expectancy, finances, and health insurance coverage.

The effectiveness of bone density measurement and associated treatments for prevention of fractures. An international collaborative review

This review assesses the evidence regarding the effectiveness of bone density measurement (BDM) screening and related interventions--hormone replacement therapy (HRT) and intranasal salmon calcitonin (SCT[N])--in menopausal women to prevent fractures in later life. Data sources included systematic reviews of evidence and relevant primary studies identified through literature searches on MEDLINE and EMBASE. Study selection included trials of BDM screening programs, prospective studies examining the predictive value of BDM, randomized controlled trials, cohort studies, and case-control studies of HRT and SCT (N). The evidence was evaluated using a classification system incorporating study design and quality. Outcomes were measured in terms of relative risk of fracture for a 1 SD decrease in bone mineral density below the age-adjusted mean, relative risks or odds ratios for fractures associated with treatments, and proportion of hip fractures potentially prevented by BDM screening linked to treatments. Fair evidence from prospective cohort studies suggests that BDM can predict the risk of fractures, but not with high accuracy. Fair evidence from low-quality randomized controlled trials and observational studies suggests that HRT and SCT(N) are efficacious in preventing fractures. Good evidence supports the efficacy of these treatments in preserving bone mass, but there is fair evidence that the effect wears off after cessation of therapy. There is little evidence on the impact of screening menopausal women with BDM in association with HRT or SCT(N) treatment. Estimates based on combining existing evidence regarding the predictive value of BDM and efficacy of HRT suggests that 1-7% of hip fractures might be prevented.

Pharmacological management of osteoporosis

Pharmacological interventions for the prevention of fractures in patients with osteoporosis aim mainly at correcting the bone remodelling imbalance by either reducing bone resorption and bone turnover, or stimulating bone formation. A number of agents are currently available but only a few were evaluated under controlled conditions in clinical trials whose primary efficacy end-point was the prevention of fractures. In addition, this information was obtained in patients with postmenopausal osteoporosis mainly with prevalent vertebral fractures, and most studies published to date had the occurrence of new vertebral rather than peripheral fractures as their primary efficacy end-point. The majority of data was obtained with inhibitors of bone turnover, but the level of evidence of the antifracture efficacy of these agents varies markedly. Results of carefully performed studies are, however, available allowing rational therapeutical choices. Adequate knowledge of the benefits and side effects of pharmacological interventions combined with other measures which improve bone health and reduce complaints and risks are essential for the management of the osteoporotic patient.

Treatment of osteoporosis with bisphosphonates

Several bisphosphonates are effective for preventing bone loss associated with estrogen deficiency, glucocorticoid treatment, and immobilization, and for at least partially reversing bone loss in patients with postmenopausal osteoporosis and steroid-induced osteoporosis. The most promising of these agents are etidronate, alendronate, risedronate, and ibandronate. These drugs should have an important role in the prevention and treatment of osteoporosis; however, more research is needed regarding optimal doses and regimens (continuous versus intermittent, oral versus parenteral), comparisons with other agents, and their use in combination with other agents.

The role of estrogen in the prevention of osteoporosis

This article reviews the role and pathophysiology of estrogen in bone remodeling. The effects of estrogen intervention on bone mass and biochemical markers are discussed as well as aspects such as dose versus response, route of administration, and interactions with other agents.

A four-year randomized controlled trial of hormone replacement and bisphosphonate, alone or in combination, in women with postmenopausal osteoporosis

PURPOSE

Hormone replacement therapy (HRT) with estrogen and treatment with bisphosphonates have been shown to increase bone mineral density (BMD) in postmenopausal women. This 4-year prospective randomized study was carried out to assess the effectiveness of the combined HRT plus etidronate on BMD in postmenopausal women with established osteoporosis.

PATIENTS AND METHODS

Seventy-two postmenopausal women (mean age 64.9+/-0.5 years) attending metabolic bone disease outpatient clinics with established osteoporosis were randomly allocated into one of four treatment groups and monitored for 4 years. All patients enrolled in this study including the control group (n=18) received 1.0 g elemental calcium and 400 units vitamin D per day. The HRT group (n=18) received cyclical estrogen and progesterone; the etidronate group (n=17) received intermittent cyclical etidronate; and the combined therapy group (n=19) received both HRT and etidronate. BMD was measured in the lumbar spine and the hip before treatment and at 2 and 4 years after treatment. Changes in height were recorded, and the occurrence of new vertebral fractures were documented in comparison with the baseline radiographic evaluation. In 40 patients (10 patients per group), analysis of bone histomorphometry was carried out after 4 years of treatment.

RESULTS

In patients who received the combined therapy, BMD increased in the lumbar spine by 10.4% (P <0.001) and in the hip by 7.0% (P <0.001) at 4 years. For patients treated with ICE, these increases were 7.3% (P <0.001) and 0.9% (P <0.05), and with HRT, the increases were 7.0% (P <0.001) and 4.8% (P <0.01) in the vertebrae and femora, respectively. The group treated with calcium and vitamin D lost 2.5% (P <0.05) and 4.4% (P <0.01) of BMD in the vertebrae and femora, respectively, after 4 years. Patients who received combined therapy had significantly higher BMD in both the vertebrae and in the femora (P <0.05) in comparison with patients who were treated with HRT or etidronate alone after 4 years. In comparison with patients in the control group, there was a trend toward a lower rate of new vertebral fractures in the treatment groups. Height loss was significantly less in all three active treatment groups (HRT [P <0.001], etidronate [P <0.02], and combined therapy group [P <0.0001]), in comparison with the control group. The combined therapy group did not have a significant height loss, in comparison with the HRT (P <0.02) and the etidronate (P <0.001) groups. None of the patients had histomorphometric evidence of osteomalacia.

CONCLUSION

This 4-year randomized study showed an additive effect of etidronate and HRT on hip and spine BMD in postmenopausal women with established osteoporosis.

Long-term effects of percutaneous estradiol on bone loss and bone metabolism in postmenopausal hysterectomized women

OBJECTIVE

To determine whether percutaneous estradiol (pE2) (1.5 mg/day) is able to counteract the postmenopausal bone loss in postmenopausal hysterectomized women, in a double-blind study versus oral estriol (E3) (2 mg/day).

METHODS

The bone mineral density of the lumbar spine (LS) and of the proximal femur (PF) was measured every 3 months by dual energy X-ray absorptiometry for 2 years in 43 hysterectomized postmenopausal women (21 in the E2 group and 22 in the E3 control group), and in a subset of patients for a 3rd year. The statistical analyses were performed on Macintosh using Stat View II.

RESULTS

A significant bone loss of 1.2 (0.4%)% and of 1.3 (0.3)% per year was observed in the control group, respectively at LS and at PF, versus a significant gain of 1.2 (0.5)% per year in the treated group at the LS. No significant change at PF occurred in the treated group. In the 20 patients followed up for a 3rd year on pE2, an increase of 1.2 (0.9) and 2.5 (1.4)% at LS in the 12 former active group patients and the eight formerly control patients, respectively was seen. The same trend was observed at the proximal femur.

CONCLUSION

pE2 (1.5 mg E2) is able to counteract the postmenopausal bone loss in hysterectomized women, whereas E3 (2 mg/day administered orally) is unable to maintain bone mass.

Biochemical markers of bone metabolism: an overview

OBJECTIVES

An overview of biochemical markers of bone metabolism is presented along with indications for their clinical utilization.

DESIGN AND METHODS

The structure, cyclical metabolism, and hormone regulation of bone is reflected by markers of resorption, formation and/or turnover. Markers of resorption representing degradation of type 1 collagen, include N-telopeptides, C-telopeptides, hydroxyproline, and the collagen crosslinks pyridinoline and deoxypyridinoline; acid phosphatase, a marker of osteoclast activity, and urinary calcium are also indicators of bone resorption. Bone formation markers indicate osteoblast activity; bone-specific alkaline phosphatase and the N-terminal and C-terminal extension peptides of procollagen reflect formation of organic matrix in bone. Osteocalcin, produced by osteoblasts but also released during osteoclastic degradation, may indicate either formation when resorption and formation are coupled or turnover when they are uncoupled.

RESULTS

Bone markers respond to intervention more rapidly than techniques such bone mineral density. Resorption markers respond approximately 1 to 3 months after intervention; markers of formation respond later, after 6 to 9 months. Bone markers may add useful information for assessing fracture risk and for monitoring osteoporosis, Paget's disease of bone, cancer metastasis, and metabolic disease. Various therapeutic interventions may affect release of some bone markers.

CONCLUSION

Bone disease has high prevalence in adults so bone markers will become even more important for assessing fracture risk and monitoring therapy as populations age. Characteristics of bone markers are dependent on biology and the assay used. Substantial work remains in characterizing existing assays, identifying better markers and performing the clinical studies to define which bone markers should be measured and when.

Prevention of early postmenopausal bone loss with cyclical etidronate therapy (a double-blind, placebo-controlled study and 1-year follow-up)

The objective of the study was to evaluate the effects of cyclical therapy with etidronate and calcium on spinal and femoral bone loss in the early post menopausal period. Fifty-four women, 53 +/- 2.8 yr old (mean +/- SD) and 2.3 +/- 1.3 yr post menopause received oral doses of either 400 mg/day etidronate for 2 weeks followed by 500 mg/day elemental calcium for 11 weeks, or placebo for 14 days followed by calcium for 11 weeks, repeated over a total of 24 months. A statistically significant increase in spinal bone mineral density (BMD) was observed after 6 months in the etidronate group. At 2 yr, the mean treatment differences in spinal and femoral neck BMD were +2.93% (P < 0.02) and 2.02% (P < 0.03), respectively. Serum osteocalcin and urinary crossLaps/creatinine excretion were decreased significantly by etidronate. Etidronate was well tolerated with a safety profile similar to that of placebo. Thirty-seven women participated in a 1-yr open-label follow-up study. Twelve months after treatment withdrawal, spinal BMD in the former etidronate group decreased by 1.43% and serum osteocalcin and urinary crossLaps returned to pretreatment values. In conclusion, cyclical etidronate is an effective therapy for the prevention of both trabecular and cortical bone loss in the early menopause and has a good safety profile.

Osteoporosis: trials and tribulations

A 30-50% reduction in fracture risk produced by a drug is biologically "worthwhile." The detection of this benefit, when truly present, is a challenge requiring large studies of 3-5 years' duration, because only a small number of women at risk actually sustain a fracture during this time. For example, in any year, fractures occur in 1-2 per 100 women approximately 65 years of age, 6-10 per 100 women approximately 75 years of age, and only 1-2 per 2,000 of the 15% of women < 60 years of age with osteoporosis. An appreciation of this low annual event rate is important because (1) it helps patients to understand their illness, (2) it determines the power of clinical trials, (3) it underscores the large numbers of patients that must be treated to prevent one fracture, and (4) it underscores the need for safety, particularly in groups at low absolute risk of fracture; all are exposed to drug side effects, and the vast majority derive no benefit from treatment because they would not have had a fracture without it, despite being at risk. Few studies have met the design requirements needed to identify the antifracture efficacy of a drug when it really exists, namely, (1) large patient samples randomized to treatment or placebo for 3-4 years, (2) blinding throughout follow-up, (3) statistical analyses of preplanned comparisons using intention to treat, and (4) avoidance of statistical analyses of associations discovered by post hoc analyses. Moreover, (5) few studies have assessed long-term safety and quality of life. Consequently, the uncertainty regarding efficacy and safety of available treatments may be more of a problem of the design, execution, and interpretation of the clinical studies than of the drugs themselves. In the reduction of vertebral fracture risk, the greatest optimism exists for hormone replacement therapy (HRT) and the bisphosphonates. HRT reduces bone turnover, increases bone mineral density (BMD), and decreases vertebral fracture rates by approximately 40%, even in women > 70 years of age. Reduction in hip fracture risk with HRT has been reported in observational studies. Two rigorously conducted studies provide credible evidence that the bisphosphonate alendronate reduces the risk of vertebral and hip fractures by approximately 40-50%. Etidronate, calcitonin, and 1,25-dihydroxyvitamin D3 may reduce risk of vertebral fracture; however, problems in study design leave uncertainty. Although 2 trials using fluoride suggest a reduction in fracture rates, the more rigorously conducted trials do not, despite having adequate power to do so. Calcium supplements are likely to slow bone loss, but reduction in fracture risk is uncertain. Vitamin D and calcium supplementation reduce risk of hip fracture in nursing home residents but not in community residents. There have been no studies of the efficacy of any treatment to prevent hip or vertebral fractures in men or in corticosteroid-related osteoporosis. The treatment of osteoporosis is becoming a reality. HRT and the bisphosphonates, particularly alendronate, appear to be the best options at present.

Biochemical bone markers and bone mineral density during postmenopausal hormone replacement therapy with and without vitamin D3: a prospective, controlled, randomized study

The effects of postmenopausal hormone replacement therapy (HRT) and vitamin D on the serum concentrations of three bone biochemical markers and their associations with bone mineral density (BMD) were studied in a population-based 1-yr follow-up study. A total of 72 healthy postmenopausal women were randomized into 4 treatment groups: HRT group (sequential combination of 2 mg estradiol valerate and 1 mg cyproterone acetate), D group (vitamin D3, 300 IU/day), HRT+D group (both of the above), and placebo group (calcium lactate, 500 mg/day). Serum concentrations of osteocalcin (OC) and bone-specific alkaline phosphatase (BAP) were measured as biochemical markers of bone formation, and serum type I collagen carboxy-terminal telopeptide was measured as a marker of bone resorption at baseline and after 6 and 12 months of treatment. To investigate the associations of these markers with BMD, lumbar (L2-L4) and femoral neck BMDs were determined by dual x-ray absorptiometry at baseline and after 2.5 yr of treatment. In both hormone groups, the serum concentrations of the three bone metabolic markers had decreased after 12 months. Those of OC decreased by 29.2% (P = 0.017) in the HRT group and by 37.3% (P = 0.004) in the HRT+D group, and BAP concentrations decreased by 34.4% (P < 0.001) in the HRT group and by 36.2% (P < 0.001) in the HRT+D group. Serum type I collagen carboxy-terminal telopeptide concentrations had decreased by 21.6% (P = 0.012) in HRT group and by 14.1% (P = 0.011) in the HRT+D group. In the D group, the serum concentrations of BAP had decreased by 11.7% (P = 0.040) after 12 months, but the other two markers showed no change. The only change seen in the placebo group was a 19.2% increase in OC concentrations (P = 0.041) after 6 months, but at 12 months, the mean OC level was similar to that at baseline. After 2.5 yr, both lumbar and femoral BMD had decreased in the D group [2.1% (P = 0.022) and 3.6% (P = 0.019), respectively] and in the placebo group [3.3% (P = 0.009) and 2.7% (P = 0.010), respectively], whereas no significant changes occurred in the hormone groups. There were significant inverse correlations between the changes in lumbar and femoral BMDs and changes in all three biochemical markers (r = -0.240 through -0.336; P = 0.005-0.064). Our results suggest that HRT counteracts the biochemical changes caused by increased bone turnover associated with menopause. Importantly, the changes in bone markers correlate with long term changes in BMDs of lumbar spine and femoral neck. Low dose vitamin D treatment, however, seems to have only marginal effects on bone metabolism in early postmenopausal healthy women.

The prevention of early postmenopausal bone loss by cyclical etidronate therapy: a 2-year, double-blind, placebo-controlled study

PURPOSE

To determine whether intermittent cyclical etidronate therapy can prevent early postmenopausal bone loss.

PATIENTS AND METHOD

This was a 2-year outpatient, randomized, double-blind, placebo-controlled clinical trial. The subjects were 152 women within 1 to 10 years of the onset of menopause and bone mineral density (BMD) between 0 and -2 SD of normal values for a 50 year old woman. The women were stratified according to years since the menopause (1 to 3 years: n = 43; 4 to 6 years: n = 53; 7 to 10 years: n = 56). Measurements of lumbar spine, proximal femur and total body BMD were performed at baseline, 12 and 24 months by dual x-ray absorptiometry. Biochemical markers of bone resorption and bone formation were measured on the same visits.

RESULTS

One hundred thirty-five subjects completed the study. Mean percentage change in lumbar spine BMD (and SEM) at 2 years was +2.14 (0.47)% in the etidronate group and -1.72 (0.41)% in the placebo group. Results for lumbar spine BMD in the treated and control groups stratified according to years since the menopause were: 1 to 3 years: +1.73 (0.84)% and -3.30 (0.70)%; 4 to 6 years: +1.37 (0.88)% and -1.80 (0.61)%; 7 to 10 years: +3.42 (0.61)% and -0.38 (0.70)%. The effect of both treatment group and menopausal stratum were highly statistically significant for lumbar spine and total body BMD. Treatment group, but not stratum, was significant for BMD in the proximal femur. Markers of bone resorption and bone formation were significantly decreased by etidronate therapy.

CONCLUSIONS

Cyclical etidronate prevents bone loss in the total skeleton and at the clinically relevant sites (spine and proximal femur) even in the early postmenopausal years. Hence, it appears to be an effective and safe nonhormonal therapy in postmenopausal women with normal or low BMD.

INTRAVENOUSLY ADMINISTERED PAMIDRONATE FOR TREATING REFRACTORY PAGET'S DISEASE OF BONE

OBJECTIVE

To report our experience with the use of intravenously administered pamidronate in 16 patients with refractory Paget's disease of bone.

METHODS

We describe our treatment regimen and outline serum alkaline phosphatase levels at baseline and after pamidronate therapy in our study cohort. In addition, we summarize clinical symptoms and response to treatment.

RESULTS

Although clinical experience with pamidronate in the treatment of Paget's disease of bone has been limited in the United States, elsewhere it has been shown to be an effective agent that inhibits the increased osteoclastic activity characteristic of this disease. Accordingly, in 16 patients with Paget's disease unresponsive to various other therapies, we administered pamidronate intravenously at a dose of 30 mg in 500 mL of 5% dextrose in water during a 4-hour period once weekly for 6 weeks. Serum alkaline phosphatase was determined at baseline and at regular intervals for at least 12 months after the onset of therapy. Many of these patients reported relief of pain and an increased flexibility or range of motion after treatment. The only adverse effect reported by these patients was an acute-phase reaction during the first infusion in two patients. In all patients, serum alkaline phosphatase levels declined, and significant (P = 0.0012) decreases from baseline were noted within 6 weeks after the initial infusion. Maximal responses were generally seen within 6 months after treatment, serum alkaline phosphatase levels decreasing as much as 91% from baseline.

CONCLUSION

These data suggest that intravenous pamidronate therapy is an effective alternative to calcitonin and etidronate in the treatment of Paget's disease of bone, particularly in those patients refractory to such agents.

The management of osteoporosis

The management of osteoporosis used to centre upon investigation and treatment of patients with fracture. The spectrum has now widened to include the detection of patients at high risk of fracture before a fracture occurs. This is best achieved by consideration of clinical risk factors and the selective use of bone densitometry. The frequency of osteoporotic fractures in elderly women is such that detailed investigation of such patients is often not necessary unless the patient's bone density is outside the normal range for age. When bone density is inexplicably low, secondary causes of osteoporosis should be sought by appropriate investigations. Fracture prevention involves a correction of lifestyle factors (stopping smoking, moderating alcohol intake etc.) and achieving a total calcium intake of 1-1.5 g/day. The first line for pharmacological intervention is hormone replacement therapy because of its proven efficacy and the extensive data available documenting its safety. The bisphosphonates have comparable effects on bone density and fractures in studies extending for up to 3 years, and are increasingly used, particularly in older patients and those reluctant to take hormone replacement therapy. Other available agents have significant drawbacks, either with respect to side-effects or inconsistent documentation of efficacy and should be used only in special circumstances.

Biological and radiological responses to oral etidronate and tiludronate in Paget's disease of bone

Paget's disease of bone is characterized by a high bone turnover. Therefore, antiresorbing agents such as bisphosphonates are clearly indicated. However, as they accumulate in the pagetic lesions, they could produce some focal defects of bone mineralization. In a double-blind study, we have had the opportunity to compare the effects of tiludronate and of etidronate (both at a fixed dose of 400 mg/day orally) on the radiological changes of 12 patients suffering from Paget's disease of bone. After breaking the code, good agreement was observed between the radiological evaluations and the applied therapy: All positive bone balances were observed in the tiludronate group, except for three questionable densifications in the etidronate group, and the negative bone balances in the etidronate group. This confirms our previous experience with etidronate in Paget's disease when X-ray films of the lesions are followed sequentially during therapy.

Calcitonin versus etidronate for the treatment of postmenopausal osteoporosis: a meta-analysis of published clinical trials

This review examines the evidence on the efficacy of calcitonin and etidronate in the prevention of osteoporosis and osteoporotic fractures. MEDLINE was searched for clinical trials calcitonin or etidronate and reviews of the treatment of postmenopausal osteoporosis. The reference sections of the papers retrieved were again searched for trials on the treatments of interest. Two people independently collected data from the trials that met the inclusion criteria of the study. Weighted means in the change in bone mineral density (BMD) and differences in vertebral fracture rates were computed for calcitonin and etidronate separately. The existence of publication bias was investigated by funnel plots of effect size against sample size. Eighteen clinical trials and calcitonin and six with etidronate were included in the meta-analysis. The pooled change in vertebral BMD at the end of the studies was 1.97 (95% CI 1.77 to 2.17) with calcitonin and 3.20 (95% CI 2.92 to 3.48) with etidronate. Pooled change in proximal femur BMD was 0.32 (95% CI -0.27 to 0.91) with calcitonin and 2.42 (95% CI 2.16 to 2.68) with etidronate. The aggregated number of vertebral fractures prevented by the treatment was 59.2 per 1000 patient-years (95% CI 55.1 to 63.3) for calcitonin and 28.3 (95% CI 26.2 to 30.4) for etidronate. With the available evidence we cannot establish the superiority of either of the two drugs for the treatment of postmenopausal osteoporosis. The clinical trials are particularly lacking in data on hip fracture, the most important consequence of osteoporosis. In this situation consideration of the relative costs of the drugs is prominent.

Intermittent Etidronate partially prevents bone loss in hirsute hyperandrogenic women treated with GnRH agonist

Treatment with gonadotropin-releasing hormone (GnRH) agonist leads to enhanced bone turnover and accelerated bone loss in premenopausal women with endometriosis, uterine leiomyomatomas and hirsutism. Sodium etidronate is a powerful inhibitor of bone resorption which had been proven efficacious in the prevention and treatment of postmenopausal osteoporosis. The objective of this study was to evaluate the skeletal effects of 6 months of therapy with the depot preparation of the GnRH agonist triptorelin (decapeptil 3.75 mg intramuscularly every 4 weeks) in 24 hirsute patients, aged 24-33 years, with hyperandrogenic chronic anovulation. Ten patients also received cyclical etidronate in an oral dose of 400 mg/day for 2 weeks, followed by an 11-week period of 500 mg/day elemental oral calcium (one cycle). The remaining 14 patients received 500 mg/day of elemental calcium continuously. After 6 months all treatments were discontinued for at least a further 6 months. Bone mineral density (BMD) at lumbar spine and hip (dual-energy X-ray absorptiometry, Sophos LXRA, France) and biochemical markers (serum alkaline phosphatase, osteocalcin, urinary N-telopeptide and hydroxyproline/creatinine ratio) were evaluated at baseline, 6 months and 12 months. In the group given GnRH agonist alone BMD fell significantly at all measured skeletal sites during the first 6 months. In the patients treated with etidronate a significant decrease in BMD was observed at lumbar spine but not in the femoral neck and trochanter, and the changes at lumbar spine and trochanter were significantly smaller than those in the control group. At 6 months bone turnover was also increased in patients treated with GnRH and calcium. Cyclical etidronate prevented the increase in biochemical markers of bone formation and resorption, with the exception of calcium/creatinine excretion, which was significantly increased in both groups. Six months after treatment withdrawal BMD did not recover in either group. Biochemical markers (N-telopeptide, serum alkaline phosphatase) remained increased in those patients previously treated with calcium alone while they remained close to baseline values in the patients treated with cyclical etidronate. Our study indicates that: (1) GnRH agonist therapy causes remarkable bone loss in young individuals with androgen excess who are expected to have increased bone mass; (2) this bone loss can be partially prevented by intermittent cyclical etidronate therapy.

Bisphosphonate therapy

The bisphosphonates are long-lived synthetic analogs of pyrophosphate, a natural, short-lived inhibitor of bone. Oral doses share similar qualities (ie, they inhibit bone resorption, poor absorption, and potential gastrointestinal irritants), but each one has a unique spectrum of potency and a probable mechanism of action. The parent compound, etidronate, was first used in multicentered trials for the treatment of primary osteoporosis and showed some success in increasing bone density and perhaps controlling fracture rates. The recently approved drug alendronate is a more potent agent than etidronate, produces a greater increase in bone density, and decreases fractures. Oral and intravenous pamidronate have similar positive effects on bone density. Studies with tiludronate, risedronate, and clodronate show similar promise as therapeutic agents.

Current and potential future drug treatments for osteoporosis

There has been a major interest in the drug treatment of osteoporosis and an increase in the number of drugs available in most countries. The ideal drug (one which increases or restores bone density and trabecular connectivity) is still not available. However, in patients with relatively preserved trabecular connectivity and moderately reduced bone density, several agents have shown substantial clinical benefit. Oestrogens are still the mainstay of drug treatment, but the risks of breast cancer versus the cardiovascular and skeletal benefits with long term use have to be assessed in the individual. Newer tissue specific oestrogens show some promise in this respect. The bisphosphonates and possibly fluoride are likely to be the major alternatives to oestrogens in the medium term. The newer bisphosphonates, alendronate and in the future risedronate, are likely to supersede etidronate. Calcitriol probably has a limited role, confined to those patients in whom HRT or bisphosphonates are not appropriate. Calcium supplementation, or an increase in dietary intake if deficient, irrespective of which agent is used, is also of benefit. In older patients there is considerable support for using a combination of calcium and vitamin D. Whether combination treatment, for example oestrogens, bisphosphonates, and calcium together, will result in greater efficacy remains to be conclusively shown, but may be an attractive option in younger patients with higher bone turnover. Apart from fluoride, bone formation stimulators are unlikely to have a major role until the next century, although it may be possible to use growth factors as part of an ADFR regimen (A = activate remodelling, D = depress resorption, F = free formation, and R = repeat). This is still an important theoretical approach and needs further work with newer agents to see if increased efficacy can be found. In addition sequential treatment may be necessary in view of the limited time periods over which particular agents, such as intermittent fluoride (four years), have been examined, and this will have to be individually tailored. Other approaches include trying to increase peak bone mineral density, although influencing the young to prevent a disease that may not manifest itself for half a century is daunting.

Prevention of hip fractures: drug therapy

Drug therapy to prevent hip fractures may be considered for postmenopausal women with low bone mass and elderly people with risk factors for hip fracture. As most hip fractures occur 25 years or more after menopause, drug therapy may have to be prescribed for many years to be effective. A preventative drug should be effective, safe, and without side effects. Estrogen therapy decreases bone loss and hip fracture incident, but the effect wears off when treatment is stopped. The positive effect of estrogens on cardiovascular disease should be balanced against the increased risk of breast cancer with long-term use. The newer bisphosphonates are potent inhibitors of bone resorption and decrease bone loss substantially. Again, the effect may wear off after the drug is stopped. The bisphosphonates appear to be safe, but long-term data are lacking. Calcium and/or vitamin D may prevent bone loss in late postmenopausal women and elderly people. The combination was shown to prevent hip fractures and other peripheral fractures in elderly nursing home residents. No single drug will be used more than 10-15 years. Therefore, a public health strategy should be developed with a logical sequence of drug and nondrug interventions for the successful prevention of hip fractures.

Alendronate treatment for osteoporosis: a review of the clinical evidence

Bisphosphonates have recently gained an increasing role in the management of osteoporosis. The aminobisphosphonate, alendronate has recently been introduced as a new agent for the treatment of postmenopausal osteoporosis. This paper reviews the clinical evidence for the use of this agent and seeks to assess its place in osteoporosis management.