Practical clinical application of biochemical markers of bone turnover: Consensus of an expert panel

Discontinuation of hormone therapy and bone mineral density: does physical activity modify that relationship?

OBJECTIVE

Hormone therapy can positively impact bone mineral density after menopause. We explored bone mineral density change in postmenopausal women who discontinued hormone therapy after the Women's Health Initiative landmark 2002 trial results were published. We secondarily explored whether usual physical activity modified the results.

METHODS

Postmenopausal women participating in the Buffalo OsteoPerio study with information on hip bone density, hormone therapy use, and self-reported physical activity at two time points (1997-2001; 2002-2007) were included (N = 961). Hormone therapy included three groups according to use at baseline and year 5 (non/non; current/non; current/current).

RESULTS

At baseline (mean age, 65.9 years; SD, 6.7 years), 480 women were not using hormone therapy, while 481 were current users. Between the baseline and 5-year visits, 336 women using hormone therapy discontinued. Baseline total hip bone density was highest in current users. After 5 years, those who continued hormone therapy exhibited no bone loss; those who discontinued exhibited the greatest loss at the total hip of -0.021 gm/cm2. Women who never used hormone therapy exhibited some loss of -0.012 gm/cm2. Usual physical activity did not appreciably impact change in bone density in any group.

CONCLUSIONS

This prospective observational study explored the 5-year change in bone mineral density among older postmenopausal women after the landmark 2002 hormone therapy trial findings were released. We found bone density decreased in never-users and in women who discontinued use. Bone density was maintained in current users. Although usual physical activity did not mitigate bone loss, targeted physical activity regimens should be investigated.

Effect of Vitamin K2 Alone or in Combination on Various Bone Turnover Markers Amongst Postmenopausal Females

Background

Osteoporosis is common in postmenopausal women. Some studies have demonstrated the usefulness of vitamin K through the action of bone-specific proteins and osteoblast and osteoclast activities. However, no systematic review had explored this aspect in postmenopausal women. Hence, this systematic review aimed to explore the effect of vitamin K₂ alone or in combination with other agents (vitamin D₃ or calcium) on various bone turnover markers (BTMs) and bone mineral density (BMD) in postmenopausal women.

Methods

MEDLINE, ScienceDirect, PubMed, and Google Scholar were searched to identify relevant studies using specific inclusion criteria. Data extraction and quality assessment were carried out using standardized tests, and the results were narratively synthesized and presented in the form of tables.

Results

Vitamin K₂ was beneficial in inducing an improvement or preventing deterioration, as evidenced by the BMD and osteocalcin (OC), undercarboxylated OC (ucOC), carboxylated OC (cOC), and γ-carboxylated OC levels. However, its effect was not conclusive when procollagen type 1 N-terminal propeptide, carboxyterminal propeptide of type I procollagen, C-terminal telopeptide of type I collagen, bone alkaline phosphatase, deoxypyridinoline, and N-terminal telopeptide levels (NTX) and ucOC:cOC or cOC:ucOC, and NTX:creatinine ratios were examined.

Conclusions

Vitamin K₂ supplementation combined with vitamin D and calcium was found to be advantageous. However, vitamin K₂ supplementation cannot replace the existing treatment options. In addition, vitamin K₂ should be used with caution, considering its interactions with food and other drugs.

Pelvic fractures and changes in bone mineral density after radiotherapy for cervical, endometrial, and vaginal cancer: A prospective study of 239 women

BACKGROUND

Advances in radiotherapy (RT) have led to improved oncologic outcomes for women with gynecologic cancers; however, the long-term effects and survivorship implications need further evaluation. The purpose of this study was to determine the incidence of pelvic fractures and changes in bone mineral density (BMD) after pelvic RT.

METHODS

Two hundred thirty-nine women who had pelvic RT for cervical, endometrial, or vaginal cancer between 2008 and 2015 were prospectively studied. BMD scans and biomarkers of bone turnover were obtained at the baseline and 3 months, 1 year, and 2 years after RT. Imaging studies were assessed for pelvic fractures for up to 5 years. Patients with osteopenia, osteoporosis, or pelvic fractures at any point were referred to the endocrinology service for evaluation and treatment.

RESULTS

The median age at diagnosis was 51 years; 132 patients (56%) were menopausal. The primary diagnoses were cervical (63.6%), endometrial (30.5%), and vaginal cancer (5.9%). Sixteen patients (7.8%; 95% confidence interval, 4.5%-12.4%) had pelvic fractures with actuarial rates of 3.6%, 12.7%, and 15.7% at 1, 2, and 3 years, respectively. Fractures were associated with baseline osteoporosis (P < .001), higher baseline bone-specific alkaline phosphatase (P < .001), and older age (P = .007). The proportion of patients with osteopenia/osteoporosis increased from 50% at the baseline to 58%, 59%, and 70% at 3 months, 1 year, and 2 years, respectively.

CONCLUSIONS

A high proportion of women had significant decreases in BMD after pelvic RT, with 7.8% diagnosed with a pelvic fracture. BMD screening and pharmacologic intervention should be strongly considered for these high-risk women.

Effect of weight loss on bone metabolism in postmenopausal obese women with osteoarthritis

BACKGROUND

The choice of hypocaloric diets in obesity can affect bone health.

AIMS

The aim of this study is to assess the effect of a hypocaloric diet in postmenopausal obese women and to determine the influence of weight reduction on bone metabolism.

METHODS

This was a non-randomised, single-treatment study in 96 postmenopausal women with a body mass index (BMI) greater than 35kg/m² and osteoarthritis. The patients received a formula diet with two intake levels of a normocaloric hyperproteic formula (1035kcal (25% protein)). Anthropometry and biochemistry with CrossLaps, osteocalcin, parathyroid hormone (PTH) and 25-OH vitamin D were measured. Consumption of protein, calcium and vitamin D were determined at the beginning of and 3 and 6 months into the study. The response to treatment was compared (high-responder (HR): weight loss greater than 15%, and low-responder (LR): weight loss less than 15%).

RESULTS

The mean age was 64.2 (7.5) years. After 6 months of treatment, a weight loss of 10.2% (8.2-13.8) was observed. There was a significant increase in vitamin D (HR: 21.8% (36.2) vs. LR: 22.7% (36.9), p=0.93) and CrossLaps (HR: 26.8% (19.5-35.2)) vs. LR: 13.3% (-6.1 to 27.9), p=0.01). The loss of more than 15% of initial body weight was an independent risk factor for an increase in CrossLaps (OR: 4.22 (1.1-16.8), p=0.04).

CONCLUSIONS

In postmenopausal obese women, weight loss was associated with an increase in the biochemical parameters of bone resorption. The increase in resorption parameters was related to the magnitude of weight loss.

Biochemical markers of aging for longitudinal studies in humans

Much progress has been made in the past decades in unraveling the mechanisms that are responsible for aging. The discovery that particular gene mutations in experimental species such as yeast, flies, and nematodes are associated with longevity has led to many important insights into pathways that regulate aging processes. However, extrapolating laboratory findings in experimental species to knowledge that is valid for the complexity of human physiology remains a major challenge. Apart from the restricted experimental possibilities, studying aging in humans is further complicated by the development of various age-related diseases. The availability of a set of biomarkers that really reflect underlying aging processes would be of much value in disentangling age-associated pathology from specific aging mechanisms. In this review, we survey the literature to identify promising biochemical markers of aging, with a particular focus on using them in longitudinal studies of aging in humans that entail repeated measurements on easily obtainable material, such as blood samples. Our search strategy was a 2-pronged approach, one focused on general mechanisms of aging and one including studies on clinical biomarkers of age-related diseases.

[Laboratory evaluation of bone metabolism index using elecsys 2010.]

BACKGROUND

Bone markers can provide a prognostic information about the risk of osteoporotic fracture and are useful tools for monitoring the efficacy of antiresorptive therapy. We evaluated the analytical performance of the bone markers of Elecsys 2010 (Roche Diagnostics Corp., Indianapolis, USA).

METHODS

We evaluated the analytical performance of the Elecsys 2010 for serum parathyroid hormone (PTH), osteocalcin, and serum bone-derived degradation products of type I collagen C-telopeptide (S-CTX) using control material and patients' specimens. For the comparison studies, an immunoradiometric assay was used for PTH and an ELISA for serum osteocalcin and serum bone-derived degradation products of type I collagen N-telopeptide (S-NTX). We established the reference intervals of S-CTX and serum osteocalcin by analyzing 4569 Korean healthy subjects according to sex and age.

RESULTS

Within-run and total CV of most items were below 5% except S-CTX low level (5.42%). Elecsys 2010 showed a good linearity (r>/=0.99, P<0.01). Good correlations with other methods were found in osteolcalcin (r=0.95, P<0.01) and PTH (r=0.96, P<0.01). S-CTX showed a good correlation with S-NTX (r=0.76, P<0.01). Reference intervals of serum osteocalcin (ng/mL) and S-CTX (ng/mL) were 9.58-33.62 and 0.18-0.89, respectively, in adult male, 8.00-31.46 and 0.11-0.81 in 31-50 years old female, and 8.30-43.50 and 0.11-1.00 in 51-80 years old female.

CONCLUSIONS

Elecsys 2010 bone markers showed a satisfactory precision, linearity, and a good correlation with other methods. With its 'one system-many capabilities' features, Elecsys 2010 would be a useful tool for measuring bone metabolism indices.

Bone remodeling and calcium homeostasis in patients with spinal cord injury: a review

Patients with spinal cord injury exhibit early and acute bone loss with the major functional consequence being a high incidence of pathological fractures. The bone status of these patients is generally investigated by dual-energy x-ray absorptiometry, but this technique does not reveal the pathophysiological mechanism underlying the bone loss. Bone cell activity can be indirectly evaluated by noninvasive techniques, including measurement of specific biochemical markers of bone formation (such as osteocalcin or bone-alkaline phosphatase) and resorption (such as procollagen type I N- or C-terminal propeptide). The bone loss in spinal cord injury is clearly due to an uncoupling of bone remodeling in favor of bone resorption, which starts just after the injury and peaks at about 1 to 4 months. Beyond 6 months, bone resorption activity decreases progressively but remains elevated for many years after injury. Conversely, bone formation is less affected. Antiresorptive treatment induces an early and acute reduction in bone resorption markers. Level of injury and health-related complications do not seem to be implicated in the intensity of bone resorption. During the acute phase, the hypercalcemic status is associated with the suppression of parathyroid hormone and vitamin D metabolites. The high sensitivity of these markers after treatment suggests that they can be used for monitoring treatment efficacy and patient compliance. The concomitant use of bone markers and dual-energy x-ray absorptiometry may improve the physician's ability to detect patients at risk of severe bone loss and subsequent fractures.

Biochemical markers in osteoporosis: usefulness in clinical practice

Currently, the measurement of bone remodeling biomarkers is an innovate proposal in clinical evaluation of patients with osteoporosis. Its use may identify patients at increased risk of fracture as well as monitoring therapeutic efficacy. Because they constitute a relatively inexpensive non-invasive measurement, its use should be widespread for serial and frequent measurements of bone turnover. However, their analytical and biological variability limits their clinical applicability.

Monitoring pharmacological therapy for osteoporosis

Osteoporosis is a common disease characterized by low bone strength that increases the risk of fractures. The consequences of fractures include increases in morbidity, mortality, and healthcare costs. Randomized clinical trials have shown that pharmacological therapy can reduce the risk of fractures. In clinical practice, however, failure to achieve optimal therapeutic benefit is common for reasons that include taking medication incorrectly, stopping it prematurely, malabsorption, and the presence of unrecognized diseases or conditions with adverse skeletal effects. Monitoring for anti-fracture effectiveness in individual patients is limited by the absence of clinical tools to directly measure bone strength. It is therefore necessary to monitor therapy with biomarkers such as bone mineral density and bone turnover markers. This is a review of the utility of these tools in the care of individual patients.

Reference intervals of biochemical bone turnover markers for Saudi Arabian women: a cross-sectional study

Biochemical bone turnover markers (BTMs) provide important information on the diagnosis, therapy and monitoring of metabolic bone diseases including osteoporosis. One goal of antiresorptive therapy in women is to decrease biochemical BTMs to the lower half of reference intervals for healthy pre-menopausal counterparts, using newly developed automated assays of such markers. The main objectives of the present study were to: (1) establish reference interval values for the following biochemical BTMs: serum osteocalcine (s-OC), bone alkaline phosphatase (s-bone ALP), procollagen type 1 N-terminal propeptide (s-PINP), crosslinked C-terminal telopeptide of Type 1 collagen (s-CTX), tartarate-resistant acid phosphatase isoform 5b (s-TRACP-5b) and urinary: CTX (u-CTX), N-telopeptides of type 1 collagen (u-NTX), pyridinoline (u-PYD) and deoxypyridinoline (u-DPD) in randomly selected Saudi healthy pre-menopausal women; (2) study the changes in biochemical BTMs in relation to age in pre- and post-menopausal women and the factors reported to influence bone turnover and (3) determine the effect of menopausal status on BTMs. A total of 2125 women were studied [including (n=1557) pre-, and (n=568) post-menopausal women, respectively, aged 20-79 years]. A total of 765 healthy pre-menopausal women (aged 35-45 years) were used to establish reference intervals for biochemical BTMs. All women studied were medically examined and had their bone mineral density (BMD) values obtained for the lumbar spine (L(1)-L(4)) and femoral neck according to detailed inclusion criteria. In all women, values of biochemical BTMs, decreased with increasing age up to the age of 45 years, increased steeply among women in their 50s and remained increased in post-menopausal women. Significant increases were evident in all biochemical BTMs in post-menopausal women with >5 years since menopause with the exception of s-OC, u-DPD, and u-PYD. Using stepwise multiple linear regression analysis, several variables were identified (depending on the BTM) as determinants of BTMs including age, BMI, parity, FSH, LH, PTH, s-Ca, s-Mg, s-PO(4) and 25(OH)D. In the reference intervals group, there are no significant correlations between any of the biochemical BTMs and age of menarche, day of menstrual cycle, physical activity, total daily dietary calcium and caffeine intakes and parity. It is recommended that the age range 35-45 years should be used when establishing biochemical BTMs reference intervals in Saudi Arabian pre-menopausal women.

The efficacy of calcitriol therapy in the management of bone loss and fractures: a qualitative review

Osteoporosis, a skeletal disorder characterized by a reduction in bone strength, increases fracture risk. Primary osteoporosis is usually a result of reduced bone mineral density as a consequence of natural aging. Secondary osteoporosis is usually a result of a disease, such as cystic fibrosis, or medical treatment, such as corticosteroids or cancer treatment.

INTRODUCTION

Currently, ten million Americans are osteoporotic and an additional 34 million have the precursor condition, osteopenia. Osteoporosis leads to 1.5 million fractures and 500,000 hospitalizations annually. Osteoporosis-related fractures increase mortality and reduce quality of life. Calcitriol, the active form of vitamin D, regulates intestinal calcium absorption, among other actions. During the past four decades, many clinical trials investigating the effect of calcitriol on bone loss have been performed.

METHODS

We conducted a systematic qualitative review of clinical trials that assessed calcitriol for the treatment of osteoporosis and bone loss. In these clinical trials, calcitriol was used as a monotherapy and in combination with other therapeutic bone agents.

RESULTS AND CONCLUSION

Studies using calcitriol monotherapy, although not conclusive, found that calcitriol slowed the rate of bone loss in a variety of populations. Calcitriol in combination with other therapeutic bone agents was shown to have additional bone-preserving effects when compared to the use of therapeutic bone agents alone. A common side-effect of calcitriol therapy was hypercalcemia and hypercalciuria, but the degree of hypercalcemia was mild. Recent research found that intermittent dosing can reduce hypercalcemia rates. Calcitriol, alone or in combination with other agents, should be considered for the therapy of osteoporosis.

Management of osteoporosis in postmenopausal women: 2010 position statement of The North American Menopause Society

OBJECTIVE

To update the evidence-based position statement published by The North American Menopause Society (NAMS) in 2006 regarding the management of osteoporosis in postmenopausal women.

METHODS

NAMS followed the general principles established for evidence-based guidelines to create this updated document. A panel of clinicians and researchers expert in the field of metabolic bone diseases and/or women's health was enlisted to review the 2006 NAMS position statement, compile supporting statements, and reach consensus on recommendations. The panel's recommendations were reviewed and approved by the NAMS Board of Trustees.

RESULTS

Osteoporosis, which is especially prevalent among older postmenopausal women, increases the risk of fractures. Hip and spine fractures are associated with particularly high morbidity and mortality in this population. Given the health implications of osteoporotic fractures, the primary goal of osteoporosis therapy is to prevent fractures, which is accomplished by slowing or stopping bone loss, maintaining bone strength, and minimizing or eliminating factors that may contribute to fractures. The evaluation of postmenopausal women for osteoporosis risk requires a medical history, physical examination, and diagnostic tests. Major risk factors for postmenopausal osteoporosis (as defined by bone mineral density) include advanced age, genetics, lifestyle factors (such as low calcium and vitamin D intake, smoking), thinness, and menopause status. The most common risk factors for osteoporotic fracture are advanced age, low bone mineral density, and previous fracture as an adult. Management focuses first on nonpharmacologic measures, such as a balanced diet, adequate calcium and vitamin D intake, adequate exercise, smoking cessation, avoidance of excessive alcohol intake, and fall prevention. If pharmacologic therapy is indicated, government-approved options are bisphosphonates, selective estrogen-receptor modulators, parathyroid hormone, estrogens, and calcitonin.

CONCLUSIONS

Management strategies for postmenopausal women involve identifying those at risk for fracture, followed by instituting measures that focus on reducing modifiable risk factors through dietary and lifestyle changes and, if indicated, pharmacologic therapy.

The utility of changes in serum levels of C-terminal telopeptide of type I collagen in predicting patient response to oral monthly ibandronate therapy

Bone turnover markers may provide a more rapid indication of patient response to osteoporosis treatment than bone mineral density (BMD) measurements. This post hoc analysis of data from the MOBILE (Monthly Oral iBandronate In LadiEs) study assessed the relationship between increases in BMD at 12 mo from baseline after starting ibandronate treatment and changes in bone resorption marker serum C-terminal telopeptide of type I collagen (sCTX) from baseline at 3 and 6 mo. MOBILE enrolled postmenopausal women aged 55-80 yr with mean lumbar spine (LS) BMD T-score of -2.5 to -5.0. This analysis included women who received 150-mg monthly oral ibandronate (n=323). A high proportion of women were classified as BMD responders after 1 yr (BMD increase was >/=0%, i.e., 74-91% depending on skeletal site; BMD increase was >/=3%, i.e., 34-67%). Women with larger decreases in sCTX were more likely to be BMD responders. The percent increase in LS BMD at 12 mo was significantly associated with the percent decrease in sCTX at 3 mo from baseline (Pearson correlation coefficient: -0.19, p=0.0016). In linear regression models, percent decrease in sCTX at 3 mo from baseline was a significant predictor of 1-yr LS BMD response (R(2)=0.61, p=0.0007). These data suggest that 3-mo changes in sCTX levels are associated with 1-yr LS BMD increases in postmenopausal women treated with once-monthly oral ibandronate.

Correlation of bone mineral density with biochemical markers in post menopausal women

To evaluate the magnitude of bone loss in postmenopausal women and to study the effect of a selective estrogen Receptor Modulator, raloxifene, on bone loss by quantitative ultrasound of calcaneus and serum bone specific alkaline phosphatase (BAP). Postmenopausal women with ostesopenia/osteoporosis were assigned randomly to receive placebo (n=30) or raloxifene (60mg/d, n=30) with calcium (500mg/day) and vitamin D (250 IU/day). The bone mineral density (BMD) and BAP levels were measured at the beginning of therapy and six months later. They were subjected to statistical analysis (t test, p value) using SPSS statistical package. 70% of postmenopausal women suffered from osteopenia/osteoporosis. After raloxifene therapy, there was improvement in the BMD but this was not statistically significant (p>0.05). There was a fall in the value of serum BAP by 26.6% (p<0.05). Raloxifene has a favourable effect on bone turnover as evident from changes in BMD and a significant fall in serum BAP.

Short‐term growth and bone turnover in children undergoing occlusive steroid (‘Wet‐Wrap’) dressings for treatment of atopic eczema

To assess the effects of steroid wet-wrap therapy on short-term growth and bone turnover, eight prepubertal (M:F,5:3) children with a median age of 5.1years (range 3.3-8.8) were studied over a 2-week period prior to therapy and at 2-week intervals during therapy. Short-term growth was assessed by measuring lower leg length velocity (LLLV) by knemometry and bone and collagen turnover was assessed by urinary deoxypyridinoline crosslink excretion corrected for creatinine excretion (DPD). Median duration of study during occlusive dressings was 12 weeks (range 2-18). Topical beclomethasone dipropionate diluted 1:10 or 1:4 in white soft paraffin was applied under tubular (Tubifast) bandages in 7/8 children. Median LLLV before and during therapy were 0.43 mm/week (10(th),90(th) centile; 0.0,0.7) and 0.42 mm/week (10(th),90(th) centile; -0.35,1.01), respectively (not significant). Median DPD before and during therapy were 25.9 nmol/l/creatinine (10(th),90(th) centile; 20.8, 33.0) and 26.3 nmol/l/creatinine (10(th),90(th) centile; 21.7, 34.1) respectively (not significant). Non-invasive assessment of the effects of steroid wet-wrap therapy can be performed in children with eczema. These preliminary results show no substantial growth promoting or adverse effects of therapy.

Screening for osteoporosis in the adult U.S. population: ACPM position statement on preventive practice

CONTEXT

Osteoporosis is a common and costly disease that is associated with high morbidity and mortality. There is a lack of direct evidence supporting the benefits of bone mineral density (BMD) screening on osteoporosis outcomes. However, there is indirect evidence to support screening for osteoporosis given the availability of medications with good antifracture efficacy. This paper addresses the position of the American College of Preventive Medicine (ACPM) on osteoporosis screening.

EVIDENCE ACQUISITION

The medical literature was reviewed for studies examining the benefits and harms of osteoporosis screening. An overview is also provided of available modalities for osteoporosis screening, risk-assessment tools, cost effectiveness, benefits and harms of screening, rationale for the study, and recommendations from leading health organizations and ACPM. A review was done of English language articles published prior to September 2008 that were retrieved via search on PubMed, from references from pertinent review or landmark articles, and from websites of leading health organizations.

EVIDENCE SYNTHESIS

There were no randomized controlled trials (RCTs) of osteoporosis screening on fracture outcomes. However, there was one observational study that demonstrated reduced fracture incidence among recipients of BMD testing. Dual energy x-ray absorptiometry is currently one of the most widely accepted and utilized methods for assessing BMD. Other potential tests for detecting osteoporosis include quantitative ultrasound, quantitative computer tomography, and biochemical markers of bone turnover. Testing via BMD is a cost-effective method for detecting osteoporosis in both men and women. Osteoporosis risk-assessment tools such as the WHO fracture-risk algorithm are useful supplements to BMD assessments as they provide estimates of absolute fracture risks. They can also be used with or without BMD testing to assist healthcare providers and patients in making decisions regarding osteoporosis treatments.

CONCLUSIONS

All adult patients aged >or=50 years should be evaluated for risk factors for osteoporosis. Screening with BMD testing for osteoporosis is recommended in women aged >or=65 years and in men aged >or=70 years. Younger postmenopausal women and men aged 50-69 years should undergo screening if they have at least one major or two minor risk factors for osteoporosis. It is also recommended that clinicians consider using an osteoporosis risk-assessment tool to evaluate absolute fracture risk to determine appropriate osteoporosis therapies.

2008 Santa Fe Bone Symposium: update on osteoporosis

The Ninth Annual Santa Fe Bone Symposium was held on August 1-2, 2008, in Santa Fe, New Mexico, USA. The symposium faculty presented the current best evidence on selected topics of clinical relevance in the fields of osteoporosis, metabolic bone disease, and assessment of skeletal health. The educational venues were in the form of didactic presentations, panel discussions, challenging cases, and numerous interactive discussions. Knowledge of basic science and clinical trials was applied to real-world patient scenarios that were discussed by faculty experts and clinician participants. Topics included an update on the rationale and development of new agents for the treatment of osteoporosis, the use of bone turnover markers in clinical practice, hospital-based pathways for the management of hip fracture patients, injectable bisphosphonates for the treatment of osteoporosis, combination therapy with anabolic and antiresorptive agents, and assessment of skeletal health with devices other than central dual-energy X-ray absorptiometry. This is a collection of scientific essays based on presentations and discussions at the 2008 Santa Fe Bone Symposium.

Prolyl-hydroxyproline dipeptide in non-hydrolyzed morning urine and its value in postmenopausal osteoporosis

BACKGROUND

Owing to the high correlation between the level of prolyl-4-hydroxyproline dipeptide in non-hydrolyzed urine and that of 4-hydroxyproline in hydrolyzed urine, we examined whether the dipeptide might function as a valuable marker of bone turnover.

METHODS

Based on densitometric measurements, 68 postmenopausal women were divided into groups of non-osteopathic, osteopenic and osteoporotic subjects. The dipeptide and current urinary resorption markers were assayed in morning urine, the former using liquid chromatography, the others plus serum formation markers by means of immunoassay procedures. Together with the assay of basal levels, diet-related changes and healing effect of yearly alendronate therapy were assessed.

RESULTS

Concentration levels in controls and osteoporotic subjects differed significantly; receiver operating characteristics yielded sensitivity of 0.743, specificity of 0.908, area under curve of 0.903, and cut-off of 10.2 micromol/mmol of creatinine. Spearman rank correlation showed the highest pair coefficient between the dipeptide and osteocalcin. Diet-related changes were not found. Following therapy, a significant decline occurred already within a trimester, whilst with the other resorption markers not until 6 months.

CONCLUSIONS

The ease of the dipeptide assay in non-hydrolyzed urine surpasses that of hydroxyproline, and the results present the compound as a real competition to other commonly assessed markers in osteopathies.

Clinical challenges in the management of osteoporosis

While knowledge regarding the diagnosis and treatment of osteoporosis has expanded dramatically over the last few years, gaps in knowledge still exist with guidance lacking on the appropriate management of several common clinical scenarios. This article uses fictional clinical scenarios to help answer three challenging questions commonly encountered in clinical practice. The first clinical challenge is when to initiate drug therapy in a patient with low bone density. It is estimated that 34 million America have low bone density and are at a higher risk for low trauma fractures. Limitations of using bone mineral density alone for drug therapy decisions, absolute risk assessment and evidence for the cost-effectiveness of therapy in this population are presented. The second clinical challenge is the prevention and treatment of vitamin D deficiency. Appropriate definitions for vitamin D insufficiency and deficiency, the populations at risk for low vitamin, potential consequences of low vitamin D, and how to manage a patient with low vitamin D are reviewed. The third clinical challenge is how to manage a patient receiving drug therapy for osteoporosis who has been deemed a potential treatment failure. How to define treatment failure, common causes of treatment failure, and the approach to the management of a patient who is not responding to appropriate osteoporosis therapy are discussed.

A 10-year follow-up of the effect of continuous-combined hormone replacement therapy and its discontinuation on bone in postmenopausal women

Objective

To establish the effect on bone mineral density (BMD) of long-term (nine years) continuous-combined hormone replacement therapy (ccHRT) with estradiol valerate/medroxyprogesterone acetate (E2V/MPA) and follow-up one year after discontinuation of ccHRT.

Study design

A total of 279 women were treated with daily dosages of E2V + MPA: 1 mg + 2.5 mg (n = 69), 1 mg + 5 mg (n = 70) or 2 mg + 5 mg (n = 140) (Indivina®, Orion Pharma, Espoo, Finland) for 8.5 years; all subjects received the lowest dosage for the next six months. BMD was measured at baseline, between 6 and 12 months, annually until the end of study and at one-year postdiscontinuation of ccHRT.

Main outcome measure

Change in BMD during nine years of treatment with ccHRT and at one-year post-discontinuation of ccHRT.

Results

Progressive increase of vertebral BMD was observed with all dosage regimens throughout nine years, with corresponding reduction in the proportion of women fulfilling criteria for osteoporosis or osteopaenia. Femoral neck BMD reached a peak at about five to six years, whereas in the lumbar spine the BMD increase was sustained until the end of the study treatment. Mean BMD declined after cessation of ccHRT use but remained substantially above baseline levels. In a subset of women (n = 58) there was a rapid (≤4%) loss of vertebral BMD in the year after termination of ccHRT use. These women had lower than average BMD at baseline but no other factor was identified that distinguished them from the overall study population.

Conclusions

Low-dose ccHRT in postmenopausal women is associated with increases in lumbar spine BMD for at least nine years. These gains are not sustained after cessation of therapy but the rate of BMD loss varies between individuals.

Activity or mass concentration of bone-specific alkaline phosphatase as a marker of bone formation

BACKGROUND

Recently published data identified bone-specific alkaline phosphatase (BALP) as a good marker of bone formation in different bone diseases and osteoporosis. Two methods are available for BALP determination: one measures enzyme activity, the other its mass concentration. We compared results for BALP activity and its mass concentration in a group of 88 healthy pre- and postmenopausal women to identify which is a more useful marker for detecting early menopausal bone remodelling changes.

METHODS

We measured BALP activity and BALP mass concentration in relation to femoral neck (FN) and lumbar spine (LS) bone mineral density (BMD) and some other widely used bone markers: osteocalcin (OC), procollagen type I N-terminal propeptide (PINP) and serum C-terminal telopeptide cross-links of type I collagen (CTx) in serum samples from 50 premenopausal (age 45.9+/-4.6 years) and 38 postmenopausal (age 54.4+/-4.5 years) women.

RESULTS

Healthy postmenopausal women exhibited 34.2% (p<0.01) and 27.3% (p=0.000) higher levels of BALP activity and mass concentration than premenopausal women, respectively. At the same time, FN and LS BMD were not significantly different between the groups. CTx values were significantly higher in postmenopausal women (p=0.018), while OC and PINP were not. We observed significant correlation between BALP activity and mass concentration (r=0.85, p<0.01). The correlation between BALP activity and FN BMD or LS BMD was insignificant. BALP mass correlated significantly with LS BMD (r=-0.370, p=0.033) but not with FN BMD. As expected, we proved a significant positive correlation for both BALP methods with the other bone markers measured in our study.

CONCLUSIONS

Postmenopausal women have slightly higher bone turnover. Since LS and FN BMD were not significantly lower in our group of healthy postmenopausal women, but BALP and CTx were markedly higher, we suggest that measurements of BALP and CTx might be useful as early markers of higher bone turnover. Finally, our results did not show any differences between the clinical utility of BALP activity and BALP mass concentration measurements.

Monitoring teriparatide-associated changes in vertebral microstructure by high-resolution CT in vivo: results from the EUROFORS study

We introduce a method for microstructural analysis of vertebral trabecular bone in vivo based on HRCT. When applied to monitor teriparatide treatment, changes in structural variables exceeded and were partially independent of changes in volumetric BMD.

INTRODUCTION

Monitoring of osteoporosis therapy based solely on bone densitometry is insufficient to assess anti-fracture efficacy. Assessing bone microstructure in vivo is therefore of importance. We studied whether it is possible to monitor effects of teriparatide on vertebral trabecular microstructure independent of BMD by high-resolution CT (HRCT).

MATERIALS AND METHODS

In a subset of 65 postmenopausal women with established osteoporosis who participated in the EUROFORS study, HRCT scans of T(12), quantitative CT of L(1)-L(3), and DXA of L(1)-L(4) were performed after 0, 6, and 12 mo of teriparatide treatment (20 microg/d). We compared BMD and 3D microstructural variables in three groups of women, based on prior antiresorptive treatment: treatment-naïve; pretreated; and pretreated women showing inadequate response to treatment.

RESULTS

We found statistically highly significant increases in most microstructural variables and BMD 6 mo after starting teriparatide. After 12 mo, apparent bone volume fraction (app. BV/TV) increased by 30.6 +/- 4.4% (SE), and apparent trabecular number (app. Tb.N.) increased by 19.0 +/- 3.2% compared with 6.4 +/- 0.7% for areal and 19.3 +/- 2.6% for volumetric BMD. The structural changes were partially independent of BMD as shown by a significantly larger standardized increase and a standardized long-term precision at least as good as DXA. Patients who had shown inadequate response to prior osteoporosis treatment did show improvements in BMD and structural measures comparable to treatment-naïve patients.

CONCLUSIONS

HRCT is a feasible method for longitudinal microstructural analysis of human vertebrae in vivo, offers information beyond BMD, and is sufficiently precise to show profound effects of teriparatide after 12 mo.

Monitoring osteoporosis therapies

Postmenopausal osteoporosis (PMO) is a progressive disease of bone loss, fractures, or both. The progression of osteoporosis leads to increased mortality and morbidity and impairs quality of life. There are effective treatments that prevent bone loss, increase bone strength, and reduce fracture risk. Improvement in persistence and adherence to therapy leads to better clinical outcomes. The management of PMO is facilitated by measuring surrogate markers of the efficacy of PMO treatments: 1) bone mineral density, 2) bone turnover markers, and 3) assessment of spinal integrity by vertebral fracture assessment by dual-energy x-ray absorptiometry. Appropriate use of markers measures the patient's baseline fracture risk and monitors response to treatments. Clinicians must interpret markers in the context of a patient's fracture risk and determine the effectiveness of therapy. Integrating these markers enhances overall patient care. The surrogate markers help the clinician to achieve the goal of managing PMO; attempting to manage PMO without markers reduces the clinical management to guesswork.

Effects of continuous oral administration of phenylbutazone on biomarkers of cartilage and bone metabolism in horses

OBJECTIVE

To evaluate the effects of continuous oral administration of phenylbutazone on serum and synovial fluid biomarkers of skeletal matrix metabolism in horses.

ANIMALS

11 adult female horses without clinical or radiographic evidence of joint disease.

PROCEDURES

Horses were randomly assigned to control or treatment groups. Phenylbutazone was administered orally twice daily at a dose of 4.4 mg/kg for 3 days to the treatment group and subsequently at a dose of 2.2 mg/kg for 7 days. Serum and radiocarpal synovial fluid samples were obtained at baseline and thereafter at regular intervals for 4 weeks. Biomarkers of cartilage aggrecan synthesis (chondroitin sulfate 846) and type II collagen synthesis (procollagen type II C-propeptide) and degradation (collagen type II cleavage) were assayed. Biomarkers of bone synthesis (osteocalcin) and resorption (C-terminal telopeptide of type I collagen) were also measured.

RESULTS

No significant differences were found between control and treatment groups or temporally for the biomarkers chondroitin sulfate 846, procollagen type II C-propeptide, collagen type II cleavage, and C-terminal telopeptide of type I collagen in serum or synovial fluid. A significant increase in osteocalcin concentration occurred in synovial fluid during treatment in the treated group. No treatment effect was detected for serum osteocalcin concentration.

CONCLUSIONS AND CLINICAL RELEVANCE

Results suggested that continuous phenylbutazone administration at recommended doses altered some biomarkers in healthy equine joints after short periods of administration. Increased osteocalcin concentration may indicate an undetermined anabolic effect of phenylbutazone administration on periarticular bone or transient induction of osteogenesis in articular chondrocytes or a mesenchymal subpopulation of synoviocytes.

Bone health in men receiving androgen deprivation therapy for prostate cancer

PURPOSE

Patients with recurrent or metastatic prostate cancer generally receive androgen deprivation therapy, which can result in significant loss of bone mineral density. We explored androgen deprivation therapy related bone loss in prostate cancer, current treatments and emerging therapies.

MATERIALS AND METHODS

Literature published on the pathogenesis and management of androgen deprivation therapy related bone loss was compiled and interpreted. Recent drug therapy findings were reviewed, including treatment guidelines.

RESULTS

Men with prostate cancer often present with bone loss and the initiation of androgen deprivation therapy can trigger further rapid decreases. This results in an increased fracture risk, and greater morbidity and mortality. Early detection of osteoporosis through androgen deprivation therapy screening and prompt initiation of therapy are critical to prevent continued decreases. Lifestyle changes such as diet, supplementation and exercise can slow the rate of bone loss. Pharmacological therapy with oral and intravenous bisphosphonates has been demonstrated to prevent or decrease the bone loss associated with androgen deprivation therapy. However, important differences exist among various bisphosphonates with respect to efficacy, compliance and toxicity. Only zoledronic acid has been shown to increase bone mineral density above baseline and provide long-term benefit by decreasing the incidence of fracture and other skeletal related events in men with bone metastases.

CONCLUSIONS

Androgen deprivation therapy associated bone loss adversely affects bone health, patient quality of life and survival in men with prostate cancer. Increased awareness of this issue, identification of risk factors, lifestyle modification and initiation of bisphosphonate therapy can improve outcomes. Education of patients and physicians regarding the importance of screening, prevention and treatment is essential.

Differentiation of mononuclear precursors into osteoclasts on the surface of Si-substituted hydroxyapatite

In healthy bone, resorption and synthesis are in perfect coordination. In previous studies we demonstrated that the incorporation of silicon into the hydroxyapatite (HA) lattice enhances the proliferation and differentiation of human osteoblasts. Therefore, the aim of this study was to demonstrate the effect of silicon-substituted HA (0.8 and 1.5 wt % Si-HA) on the differentiation of mononuclear cells into osteoclasts, using two different starting cultures, peripheral blood mononuclear cells (PBMC) and monocytes expressing the CD14 antigen (CD14+). Through this study, it was possible to demonstrate that Si-HA allows the differentiation of mononuclear cells into mature osteoclasts, independent of the starting culture, PBMC or CD14+. Most of the cells on the surface of the materials expressed osteoclastic markers: actin rings, several nuclei, positivity for tartrate-resistant acid phosphatase (TRAP), and vitronectin receptor. In the presence of osteoclasts, a higher release of calcium and phosphate into the medium from the 1.5 wt % Si-HA substrate was detected when compared to the HA substrate; therefore, these results indicate higher osteoclastic resorptive activity on the 1.5 wt % Si-HA surface. Si-HA can be resorbed by cellular mechanisms and have a stimulatory effect on osteoclasts, although the underlying mechanism is still poorly understood.

Osteoporosis: differences and similarities in male and female patients

Osteoporosis is associated with decreased bone strength as a consequence of decreased bone density and altered quality. It is a result of a disruption of balance between bone breakdown and bone formation, caused by increased bone resorption by osteoclasts or without appropriate screening, one's first awareness of the disease is a fracture. It results in increased mortality and significant morbidity. In the last decade, great strides have been made in defining the diagnosis and establishing effective modes of treatment for this disorder. Our current state of knowledge indicates that although this disease affects both sexes, there are clear differences that have clinical importance.

Management of osteoporosis in postmenopausal women

OBJECTIVE

To update the evidence-based position statement published by The North American Menopause Society (NAMS) in 2002 regarding the management of osteoporosis in postmenopausal women.

DESIGN

NAMS followed the general principles established for evidence-based guidelines to create this updated document. A panel of clinicians and researchers expert in the field of metabolic bone diseases and/or women's health were enlisted to review the 2002 NAMS position statement, compile supporting statements, and reach consensus on recommendations. The panel's recommendations were reviewed and approved by the NAMS Board of Trustees.

RESULTS

Osteoporosis, whose prevalence is especially high among elderly postmenopausal women, increases the risk of fractures. Hip and spine fractures are associated with particularly high morbidity and mortality in this population. Given the health implications of osteoporotic fractures, the primary goal of osteoporosis therapy is to prevent fractures, which is accomplished by slowing or stopping bone loss, maintaining bone strength, and minimizing or eliminating factors that may contribute to fractures. The evaluation of postmenopausal women for osteoporosis risk requires a medical history, physical examination, and diagnostic tests. Major risk factors for postmenopausal osteoporosis (as defined by bone mineral density) include advanced age, genetics, lifestyle factors (such as low calcium and vitamin D intake, smoking), thinness, and menopause status. The most common risk factors for osteoporotic fracture are advanced age, low bone mineral density, and previous fracture as an adult. Management focuses first on nonpharmacologic measures, such as a balanced diet, adequate calcium and vitamin D intake, adequate exercise, smoking cessation, avoidance of excessive alcohol intake, and fall prevention. If pharmacologic therapy is indicated, government-approved options are bisphosphonates, a selective estrogen-receptor modulator, parathyroid hormone, estrogens, and calcitonin.

CONCLUSIONS

Management strategies for postmenopausal women involve identifying those at risk of low bone density and fracture, followed by instituting measures that focus on reducing modifiable risk factors through lifestyle changes and, if indicated, pharmacologic therapy.

Monitoring osteoporosis therapy: bone mineral density, bone turnover markers, or both?

Monitoring the efficacy associated with antiresorptive therapy is an intuitive yet integral part of successful osteoporosis management. Although response rates to bisphosphonates in clinical trials--as judged by changes in bone mineral density (BMD)--are generally high, a small percentage of compliant patients do not respond. Accordingly, monitoring may help identify noncompliant patients and allow for other, possibly more successful, therapeutic interventions. Dual energy x-ray absorptiometry is the accepted method of assessing BMD to determine the need for treatment and to monitor its effects. Change in BMD is considered a valid intermediate end point for efficacy of fracture risk reduction. However, clinical trials have shown that the reduction in fracture risk associated with antiresorptive therapy may occur before changes in BMD become apparent. Vertebral fracture benefit is observed even among women who maintain rather than gain BMD during antiresorptive therapy. Clinical trials show that suppression of bone turnover markers after as little as 3 months of therapy is strongly associated with reductions in risk for fracture. Although formal guidelines for monitoring bone turnover markers do not yet exist, there are data to suggest that changes in these markers are valid intermediate endpoints for efficacy of fracture risk reduction that may provide valuable additional data on therapeutic success, particularly early in treatment and before changes in BMD become apparent.

Canadian Consensus Conference on osteoporosis, 2006 update

OBJECTIVE

To provide guidelines for the health care provider on the diagnosis and clinical management of postmenopausal osteoporosis.

OUTCOMES

Strategies for identifying and evaluating high-risk individuals, the use of bone mineral density (BMD) and bone turnover markers in assessing diagnosis and response to management, and recommendations regarding nutrition, physical activity, and the selection of pharmacologic therapy to prevent and manage osteoporosis.

EVIDENCE

MEDLINE and the Cochrane database were searched for articles in English on subjects related to osteoporosis diagnosis, prevention, and management from March 2001 to April 2005. The authors critically reviewed the evidence and developed the recommendations according to the Journal of Obstetrics and Gynaecology Canada's methodology and consensus development process.

VALUES

The quality of evidence is rated using the criteria described in the report of the Canadian Task Force on the Periodic Health Examination. Recommendations for practice are ranked according to the method described in this report.

SPONSORS

The development of this consensus guideline was supported by unrestricted educational grants from Berlex Canada Inc., Lilly Canada, Merck Frosst, Novartis, Novogen, Novo Nordisk, Proctor and Gamble, Schering Canada, and Wyeth Canada.

Does alendronate prevent collapse in osteonecrosis of the femoral head?

Progression of collapse in osteonecrosis of the femoral head is related to the repair response, especially bone resorption around the necrotic region. A preliminary clinical study was done to determine whether systemic alendronate would prevent collapse and lead to pain relief in patients with osteonecrosis of the femoral head. Fourteen patients (20 hips) with osteonecrosis of the femoral head received daily administration of 5 mg alendronate (alendronate group) for 1 year. Eight patients (13 hips) with osteonecrosis of the femoral head did not receive alendronate (control group). All patients had measurements of biochemical markers of bone turnover at entry into the study, and the patients in the alendronate group repeated the measurements at 3 months, 6 months, and 12 months. All patients had clinical and plain radiographic examinations at entry into the study and at 3 months, 6 months, and 12 months. The alendronate group showed a greater decrease of biochemical marker of bone resorption than biochemical marker of bone formation. The alendronate group showed a lower frequency of collapse of the femoral head and reported less hip pain than the control group. Our results suggest alendronate has the potential to prevent collapse of the femoral head, even with extensive necrosis, presumably by inhibiting bone resorption in the necrotic region.

LEVEL OF EVIDENCE

Therapeutic study, level II (prospective comparative study). See the Guidelines for Authors for a complete description of levels of evidence.

Vitamin D insufficiency in preadolescent African-American children

To determine the proportion of vitamin D insufficiency in 6- to 10-year-old preadolescent African-American children residing in Pittsburgh, Pennsylvania and to estimate their therapeutic response to vitamin D 400 IU/day for 1-month, an open-label pre- and post-comparison of vitamin D status following vitamin D 400 IU daily for 1 month during winter and early spring was conducted. Outcomes included serum calcium, phosphorus, albumin, 25 hydroxyvitamin D [25 (OH) D], 1, 25 dihydroxyvitamin D [1, 25 (OH) (2) D], parathyroid hormone (PTH), and markers of bone turnover (serum bone-specific alkaline phosphatase, osteocalcin, and urine n-telopeptide crosslinked collagen type 1 [NTX]). Dietary intake of vitamin D was assessed using a food frequency questionnaire. Forty-one of the 42 enrolled subjects (mean age: 8.9 +/- 1.2 yrs [SD]) were analyzed, and 20/41 (49%) were vitamin D insufficient. Vitamin D insufficient group had a suggestive trend of being older (9.2 +/- 1.0 years vs. 8.5 +/- 1.3 years, p = 0.06) and more pubertally advanced (Tanner II: 7/20 vs. Tanner II: 1/21, p = 0.02). Mean dietary intake of vitamin D was 277 ( 146 IU/day (n = 41). Adequate intake for vitamin D (200 IU/day) was not met in 16/41 (39%); however, the dietary intake of vitamin D was not significantly different between the vitamin D insufficient and vitamin D sufficient groups.

Clinical use of serum and urine bone markers in the management of osteoporosis

Osteoporosis is a common disease characterized by decreased bone mass, increased bone turnover, and increased susceptibility to fracture. Almost 44 million Americans are estimated to have low bone mass, which puts them at increased risk of developing osteoporosis and fractures. Osteoporosis is diagnosed by a low bone density (BMD) measurement, because a low BMD is known to contribute to increased fracture risk, which is the main source of morbidity and mortality for osteoporosis. However, changes in bone mass and density in response to anti-resorptive therapy account for only a small portion of the predicted fracture risk reduction. Whereas dynamic changes in bone turnover, estimated by measurement of bone biochemical markers, such as breakdown products of type-I collagen and proteins secreted by osteoblasts and osteoclasts in blood and urine, can account for a major portion of anti-fracture efficacy of anti-resorptive agents. Most anti-resorptive agents act by rapidly reducing bone markers. This has led to advocacy for use of bone turnover markers, in complement to BMD measurement, in the management of osteoporosis. In general, higher bone turnover is associated with accelerated bone loss and potential deterioration in bone quality. Several clinical trials have established the potential utility of markers to identify patients with rapid bone loss, to aid in therapeutic decision-making, and to monitor therapeutic efficacy of various treatments. Elevated marker levels have been shown to be associated with increased risk of fracture in elderly women, but their utility in predicting fracture is not yet established. In this article, we provide a brief summary to primary practitioners about the role bone markers can play in the management of osteoporosis.

Conserved epitopes in human and mouse tissue-nonspecific alkaline phosphatase. Second report of the ISOBM TD-9 workshop

A panel of 19 monoclonal antibodies (MAbs) against human tissue-nonspecific (liver/bone/kidney) alkaline phosphatase (TNAP) was obtained through the ISOBM TD-9 workshop. In the present study, the reactivity of these MAbs has been characterized against mouse TNAP. A mouse embryonic stem cell line, frozen sections of long bones, alkaline phosphatase extracted from mouse bone, and serum were used as the source of TNAP for individual assays. Each MAb was tested for immunoreactivity to mouse TNAP by Western blot analysis, immunohistochemistry and enzyme immunoassay. Antibodies 314 and 315 reacted strongly with mouse TNAP in Western blots, while all other antibodies were negative. By immunohistochemistry, antibodies 314, 315 and 333 produced strong positive staining using frozen sections, while antibody 334 was moderately positive. Enzyme immunoassays indicated that MAb 333 was also able to bind to serum TNAP. These antibodies represent very useful reagents to study the pathophysiological expression of TNAP in mouse tissues and in mouse serum.

Common biochemical markers of bone turnover predict future bone loss: a 5-year follow-up study

BACKGROUND

Bone mineral density (BMD) is used to follow gain or loss of bone mass but cannot detect changes within a short period of time. Biochemical markers of bone turnover may be of value for prediction of individual bone loss.

METHODS

We studied the relation between common inexpensive markers of bone turnover (serum alkaline phosphatase (ALP), osteocalcin (OC), urinary hydroxyproline (OHPr), and calcium (Ca)), BMD, age, and menopause in a combined cross-sectional and longitudinal design comprising 429 pre- and postmenopausal randomly selected women aged 21-79 years (mean 50 years). A follow-up was initiated after 5 years (including 192 of these women), which focused on changes in bone mass and the ability of these four common markers of bone turnover (sampled at baseline) to predict future bone loss.

RESULTS

A marked increase was observed for all markers at the beginning of menopause. During the postmenopausal period ALP and Ca decreased to near premenopausal levels, while OC and OHPr remained high even 15 years after menopause. We also found inverse correlations at baseline between the bone markers and BMD, independent of the selected marker or skeletal site, r=-0.14 to -0.46, P<0.05. The correlations between ALP, OC, OHPr, and subsequent bone loss over 5 years, was significant for arm, r=-0.23 to -0.36, P<0.01. Baseline levels of all bone markers correlated significantly at group level with the 5-year follow-up of BMD for all sites. The ability of markers to predict individual bone loss was estimated by a multivariate regression model, which included baseline BMD, age, and body mass index as independent variables. ROC analysis showed a validity of approximately 76% for the forearm model, but was lower for the hip (55%) and lumbar spine (65%).

CONCLUSIONS

These data show that the common inexpensive biochemical markers of bone turnover ALP, OC, OHPr, and Ca were related to the current bone mass and, moreover, provides information about future bone loss at the individual level. Future investigations should include an evaluation of the clinical relevance of markers of bone turnover in relation to fracture risk.

The roles of bone mineral density, bone turnover, and other properties in reducing fracture risk during antiresorptive therapy

Osteoporosis is a skeletal disorder characterized by compromised bone strength and increased risk of fracture. Properties related to bone strength include rate of bone turnover, bone mineral density, geometry, microarchitecture, and mean degree of mineralization. These properties (with or without bone density) are sometimes collectively referred to as bone quality. Antiresorptive agents may reduce fracture risk by several separate but interrelated effects on these individual properties. For example, antiresorptive agents have been reported to reduce bone turnover, stabilize or increase bone density, preserve or improve microarchitecture, reduce the number or size of resorption sites, and improve mineralization. Although changes in bone architecture and mineralization are not currently measurable in clinical practice, bone turnover is assessed easily in vivo and affects the other bone properties. Moreover, antiresorptive therapies that produce larger decreases in bone turnover markers together with larger increases in bone mineral density are associated with greater reductions in fracture risk, especially at sites primarily composed of cortical bone such as the hip. Reductions in fracture risk are the most convincing evidence of good bone quality. Data from well-designed randomized clinical trials with up to 10 years of continuous antiresorptive therapy have shown that certain antiresorptive agents effectively reduce fracture risk and (together with extensive preclinical data) suggest no deleterious effects on bone quality.

Osteoporosis: underrated, underdiagnosed and undertreated

Osteoporosis is: (1) Underrated. Currently costs about 7 billion dollars annually in Australia. Has high morbidity and 2-3-fold increase in risk of death after any major osteoporotic fracture. Genetic factors contribute highly to risk, modified by lifestyle and hormonal factors. (2) Underdiagnosed. Bone density is a good predictor of subsequent risk. Anyone with a low-trauma fracture has osteoporosis unless proven otherwise. Every individual with a low trauma fracture should be investigated for exclusion of underlying osteoporosis and considered for effective treatment to reduce future fracture risk. More than 75% of women and about 90% of men with a high likelihood of osteoporosis are not investigated. (3) Undertreated. More than 75% of those affected are not treated. Effective treatments (eg, hormone replacement therapy, selective oestrogen receptor modifiers and bisphosphonates) reduce fracture risk by 30%-60%. Simple measures like vitamin D and calcium supplementation and use of hip protectors can reduce hip fractures, particularly in institutionalised and housebound elderly people

Putting evidence-based medicine into clinical practice: comparing anti-resorptive agents for the treatment of osteoporosis

OBJECTIVE

To compare the effectiveness of antiresorptive agents in reducing the risk of vertebral and non-vertebral fractures using data from published meta-analyses and the technique of adjusted indirect comparisons.

RESEARCH DESIGN AND METHODS

Pairs of agents were compared by adjusted indirect comparison of 0.56 [0.40, 0.78], respectively) in reducing the their effects relative to a common comparator (placebo) using meta-analyses published by The Osteoporosis Methodology Group and The Osteoporosis Research Advisory Group.

RESULTS

Adjusted indirect comparisons identified only one pair of agents that had significantly different effects on vertebral fracture incidence: alendronate was 34% more effective than calcitonin (Relative Risk: 0.66, 95% Confidence Interval: 0.48-0.90). Alendronate was significantly more effective than risedronate, calcitonin, estrogen, etidronate, and raloxifene (Relative Risks: 0.70 [0.49, 0.99], 0.64 [0.42, 0.98], 0.59 [0.41, 0.84], 0.52 [0.32, 0.82], and incidence of non-vertebral fractures. No other significant pairwise differences were observed.

CONCLUSIONS

The results suggest that there are differences in anti-fracture efficacy among antiresorptive agents, particularly for non-vertebral fractures. Direct head-to-head comparisons would be needed to confirm these findings but are unlikely to be conducted.

Relationship between changes in biochemical markers of bone turnover and BMD to predict vertebral fracture risk

The change in BMD is a poor predictor of vertebral fracture risk after raloxifene treatment. One-year percent change in bone turnover and BMD was used to predict vertebral fracture risk. The percent change in osteocalcin was determined to be a better predictor of vertebral fracture risk than BMD.

INTRODUCTION

The association between baseline BMD and fracture risk is well understood. However, the relationship between changes in BMD and fracture risk is not well defined. It has previously been demonstrated that BMD change was a poor predictor of vertebral fracture risk in raloxifene-treated women, whereas bone turnover markers were significantly associated with fracture risk. In the current analysis, we explore the prediction of vertebral fracture risk using changes in both BMD and bone turnover.

MATERIALS AND METHODS

The Multiple Outcomes of Raloxifene Evaluation (MORE) trial was a randomized, placebo-controlled trial of 7705 women with osteoporosis treated with raloxifene 60 or 120 mg/day for 3 years. Markers of bone turnover were measured in one-third of the study population (n = 2503), and the present analyses include these women. Logistic regression models were constructed using one-year percent changes in BMD and bone turnover and relevant baseline demographics to predict the risk of vertebral fracture with pooled raloxifene therapy at 3 years. All covariates were standardized before modeling to facilitate direct comparisons between changes in BMD and bone turnover.

RESULTS AND CONCLUSION

Prevalent vertebral fracture status (p < 0.0001), baseline lumbar spine BMD (p < 0.0001), and number of years postmenopausal (p = 0.0005) were independent predictors of fracture risk in raloxifene-treated patients. Therapy-by-change in femoral neck BMD (p = 0.02) and therapy-by-change in osteocalcin (OC; p = 0.01) were also significant for all treatment groups, indicating that changes in BMD and OC have different effects on fracture risk for the placebo and pooled raloxifene groups. The final model included significant baseline variables and change in OC (p = 0.01), whereas change in femoral neck BMD was not significant. After adjustment of each significant baseline variable, the percent change in OC was better able to predict the reduction in vertebral fracture risk than the percent change in femoral neck BMD in patients treated with raloxifene.

Clinical Use of Teriparatide in the Real World: Initial Insights

OBJECTIVE

To summarize expert opinion regarding clinical application of the recently introduced anabolic agent teriparatide [human parathyroid hormone (1-34)] in treatment of postmenopausal osteoporosis in women, and osteoporosis in men.

SUMMARY

The anabolic agent teriparatide was approved for clinical use by the Food and Drug Administration (FDA) on November 26, 2002. Since the launch of teriparatide, many more questions about clinical use of this exciting agent have emerged than there are answers provided by clinical trials or FDA-approved product labeling. A group of physicians with a broad range of experience in research and clinical applications of teriparatide met recently to address practical issues related to its use. This manuscript is a compendium of the consensus opinions of the authors that attempts to provide practical answers to many real-world questions being asked about teriparatide therapy since its approval by the FDA.

Antiresorptive treatment of postmenopausal osteoporosis: review of randomized clinical studies and rationale for the Evista alendronate comparison (EVA) trial

Standard pharmacological antiresorptive therapy for the prevention and/or treatment of postmenopausal osteoporosis now consists of four categories of drugs: estrogens, a selective estrogen receptor modulator (SERM), bisphosponates, and calcitonin. All of these drugs have been studied in randomized controlled trials, but meaningful comparisons of the efficacy of drugs have been difficult due to differences in baseline risks for fracture and differences in study design, including calcium and vitamin D supplementation, definition of fracture, and discontinuation rates. The current paper reviews results from pivotal studies of antiresorptive therapies with fracture as a primary endpoint, as well as head-to-head trials comparing these therapies using surrogate markers of fracture risk, and introduces the first head-to-head trial with fracture as a primary endpoint. The Evista Alendronate Comparison (EVA) trial, a multi-center, double-blind, double-dummy, randomized trial with two active treatment arms is currently underway to compare directly the osteoporotic fracture risk reduction efficacy of raloxifene and alendronate in postmenopausal women with osteoporosis as defined by bone mineral density. The results from this trial will permit more informed judgment by practitioners and provider groups concerning the relative clinical utility of these two drugs.

High-performance liquid chromatography method to analyze free and total urinary pyridinoline and deoxypyridinoline

The pyridinium cross-links pyridinoline (PYD) and deoxypyridinoline (DPD) are established markers of bone resorption measured in blood and urine and are used to investigate bone metabolism and manage bone diseases. Unfortunately, the currently observed interlaboratory variability caused by inconsistent assay calibration limits the optimal use of these markers. A high-performance liquid chromatography (HPLC)-based assay was developed using synthetic PYD and DPD as calibrators to analyze free and total PYD and DPD in urine. The spectroscopic characteristics of the synthetic calibrators were identical to those of calibrators isolated from bone. The mean intraassay variabilities of the HPLC method were 4.1 and 3.8%, respectively, for total DPD and PYD and 9.8 and 9.5%, respectively, for free DPD and PYD. The mean interassay variabilities were 9.1 and 8.2% for total DPD and PYD and 8.6 and 7.0% for free DPD and PYD, respectively. The mean recoveries were 98.1% for total DPD, 100.8% for total PYD, 98.6% for free DPD, and 94.9% for free PYD. The method exhibits a good correlation with a commercial immunoassay and with other HPLC assays currently used in hospital laboratories.