Trends in osteoporosis care patterns during the COVID-19 pandemic in Alberta, Canada

PURPOSE/INTRODUCTION

The objective of this study was to describe osteoporosis-related care patterns during the coronavirus disease 2019 (COVID-19) pandemic in Alberta, Canada, relative to the 3-year preceding.

METHODS

A repeated cross-sectional study design encompassing 3-month periods of continuous administrative health data between March 15, 2017, and September 14, 2020, described osteoporosis-related healthcare resource utilization (HCRU) and treatment patterns. Outcomes included patients with osteoporosis-related healthcare encounters, physician visits, diagnostic and laboratory test volumes, and treatment initiations and disruptions. The percent change between outcomes was calculated, averaged across the control periods (2017-2019), relative to the COVID-19 periods (2020).

RESULTS

Relative to the average control March to June period, all HCRU declined during the corresponding COVID-19 period. There was a reduction of 14% in patients with osteoporosis healthcare encounters, 13% in general practitioner visits, 9% in specialist practitioner visits, 47% in bone mineral density tests, and 13% in vitamin D tests. Treatment initiations declined 43%, 26%, and 35% for oral bisphosphonates, intravenous bisphosphonates, and denosumab, respectively. Slight increases were observed in the proportion of patients with treatment disruptions. In the subsequent June to September period, HCRU either returned to or surpassed pre-pandemic levels, when including telehealth visits accounting for 33-45% of healthcare encounters during the COVID periods. Oral bisphosphonate treatment initiations remained lower than pre-pandemic levels.

CONCLUSIONS

This study demonstrates the COVID-19 pandemic and corresponding public health lockdowns further heightened the "crisis" around the known gap in osteoporosis care and altered the provision of care (e.g., use of telehealth and initiation of treatment). Osteoporosis has a known substantial care and management disparity, which has been classified as a crisis. The COVID-19 pandemic created additional burden on osteoporosis patient care with healthcare encounters, physician visits, diagnostic and laboratory tests, and treatment initiations all declining during the initial pandemic period, relative to previous years.

Trends in osteoporotic fracture and related in-hospital complications during the COVID-19 pandemic in Alberta, Canada

Fragility fractures (i.e., low-energy fractures) account for most fractures among older Canadians and are associated with significant increases in morbidity and mortality. Study results suggest that low-energy fracture rates (associated with surgical intervention and outcomes) declined slightly, but largely remained stable in the first few months of the COVID-19 pandemic.

PURPOSE/INTRODUCTION

This study describes rates of low-energy fractures, time-to-surgery, complications, and deaths post-surgery in patients with fractures during the coronavirus disease (COVID-19) pandemic in Alberta, Canada, compared to the three years prior.

METHODS

A repeated cross-sectional study was conducted using provincial-level administrative health data. Outcomes were assessed in 3-month periods in the 3 years preceding the COVID-19 pandemic and in the first two 3-month periods after restrictions were implemented. Patterns of fracture- and hospital-related outcomes over the control years (2017-2019) and COVID-19 restrictions periods (2020) were calculated.

RESULTS

Relative to the average from the control periods, there was a slight decrease in the absolute number of low-energy fractures (n = 4733 versus n = 4308) during the first COVID-19 period, followed by a slight rise in the second COVID-19 period (n = 4520 versus n = 4831). While the absolute number of patients with low-energy fractures receiving surgery within the same episode of care decreased slightly during the COVID-19 periods, the proportion receiving surgery and the proportion receiving surgery within 24 h of admission remained stable. Across all periods, hip fractures accounted for the majority of patients with low-energy fractures receiving surgery (range: 58.9-64.2%). Patients with complications following surgery and in-hospital deaths following fracture repair decreased slightly during the COVID-19 periods.

CONCLUSIONS

These results suggest that low-energy fracture rates, associated surgeries, and surgical outcomes declined slightly, but largely remained stable in the first few months of the pandemic. Further investigation is warranted to explore patterns during subsequent COVID-19 waves when the healthcare system experienced severe strain.

Osteoporosis management in hematologic stem cell transplant recipients: Executive summary

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Hematopoietic stem cell transplant (HSCT) patients are living longer.

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Bone health is an important long-term comorbidity post-HSCT.

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HSCT patients are at high risk of bone loss and fragility fracture.

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HSCT patients are at high risk of bone loss and fragility fracture.

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Recommendations are provided for better monitoring of bone health.

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Recommendations include bone assessment, dietary advice and osteoporosis medication.

Background

Treatment advances have reduced the adverse events associated with hematopoietic stem cell transplant (HSCT) and led to an increased number of transplants performed. HSCT patients are living longer with concerns on long-term outcomes. Bone fragility and fracture are at the forefront for long-term morbidities post-HSCT.

Results

In HSCT recipients, evidence has accumulated to support recommendations for more extensive monitoring of bone fragility and more appropriate administration of osteoporosis pharmacotherapies for patients at high risk of bone loss and/or fracture.

Conclusion

This executive summary reports and summarizes the main recommendations published previously, including bone assessment, dietary and lifestyle recommendations and osteoporosis medication.

A scorecard for osteoporosis in Canada and seven Canadian provinces

The scorecard evaluates the burden and management of osteoporosis in Canada and how care pathways differ across Canadian provinces. The results showed there are inequities in patients' access to diagnosis, treatment, and post-fracture care programs in Canada. Interventions are needed to close the osteoporosis treatment gap and minimize these inequities.

INTRODUCTION

The purpose of this study was to develop a visual scorecard that assesses the burden of osteoporosis and its management within Canada and seven Canadian provinces.

METHODS

We adapted the Scorecard for Osteoporosis in Europe (SCOPE) to score osteoporosis indicators for Canada and seven provinces (British Columbia, Alberta, Saskatchewan, Ontario, Quebec, New Brunswick, and Newfoundland). We obtained data from a comprehensive literature review and interviews with osteoporosis experts. We scored 20 elements across four domains: burden of disease, policy framework, service provision, and service uptake. Each element was scored as red, yellow, or green, indicating high, intermediate, or low risk, respectively. Elements with insufficient data were scored black.

RESULTS

Canada performed well on several elements of osteoporosis care, including high uptake of risk assessment algorithms and minimal wait times for hip fracture surgery. However, there were no established fracture registries, and reporting on individuals with high fracture risk who remain untreated was limited. Furthermore, osteoporosis was not an official health priority in most provinces. Government-backed action plans and other osteoporosis initiatives were primarily confined to Ontario and Alberta. Several provinces (Saskatchewan, New Brunswick, Newfoundland) did not have any registered fracture liaison service (FLS) programs. Access to diagnosis and treatment was also inconsistent and reimbursement policies did not align with clinical guidelines.

CONCLUSION

Government-backed action plans are needed to address provincial inequities in patients' access to diagnosis, treatment, and FLS programs in Canada. Further characterization of the treatment gap and the establishment of fracture registries are critical next steps in providing high-quality osteoporosis care.

Efficacy of teriparatide compared with risedronate on FRAX®-defined major osteoporotic fractures: results of the VERO clinical trial

FRAX^® calculates the 10-year probability of major osteoporotic fractures (MOF), which are considered to have a greater clinical impact than other fractures. Our results suggest that, in postmenopausal women with severe osteoporosis, those treated with teriparatide had a 60% lower risk of FRAX^®-defined MOF compared with those treated with risedronate.

INTRODUCTION

The VERO trial was an active-controlled fracture endpoint clinical trial that enrolled postmenopausal women with severe osteoporosis. After 24 months, a 52% reduction in the hazard ratio (HR) of clinical fractures was reported in patients randomized to teriparatide compared with risedronate. We examined fracture results restricted to FRAX^®-defined major osteoporotic fractures (MOF), which include clinical vertebral, hip, humerus, and forearm fractures.

METHODS

In total, 1360 postmenopausal women (mean age 72.1 years) were randomized to receive subcutaneous daily teriparatide (20 μg) or oral weekly risedronate (35 mg). Patient cumulative incidence of ≥ 1 FRAX^®-defined MOF and of all clinical fractures were estimated by Kaplan-Meier analyses, and the comparison between treatments was based on the stratified log-rank test. Additionally, an extended Cox model was used to estimate HRs at different time points. Incidence fracture rates were estimated at each 6-month interval.

RESULTS

After 24 months, 16 (2.6%) patients in the teriparatide group had ≥ 1 low trauma FRAX^®-defined MOF compared with 40 patients (6.4%) in the risedronate group (HR 0.40; 95% CI 0.23-0.68; p = 0.001). Clinical vertebral and radius fractures were the most frequent FRAX^®-defined MOF sites. The largest difference in incidence rates of both FRAX^®-defined MOF and all clinical fractures between treatments occurred during the 6- to 12-month period. There was a statistically significant reduction in fractures between groups as early as 7 months for both categories of clinical fractures analyzed.

CONCLUSION

In postmenopausal women with severe osteoporosis, treatment with teriparatide was more efficacious than risedronate, with a 60% lower risk of FRAX^®-defined MOF during the 24-month treatment period. Fracture risk was statistically significantly reduced at 7 months of treatment.

CLINICAL TRIAL INFORMATION

ClinicalTrials.gov Identifier: NCT01709110 EudraCT Number: 2012-000123-41.

Bone mineral density gains with a second 12-month course of romosozumab therapy following placebo or denosumab

Romosozumab is a therapy that stimulates bone formation and reduces bone resorption. In this study of postmenopausal women with low BMD, a second course of romosozumab following a period off treatment or on denosumab increased or maintained BMD, respectively, and was well tolerated, providing insight into treatment sequence options.

INTRODUCTION

In patients with high fracture risk, therapies that stimulate bone formation provide rapid BMD gains; currently available agents, parathyroid hormone receptor agonists, are limited to a 2-year lifetime exposure and generally used for a single treatment course. However, for long-term osteoporosis management, a second treatment course may be appropriate. Romosozumab, a therapy with the dual effect of increasing bone formation and decreasing bone resorption, reduces fracture risk within 12 months. Here, we report efficacy and safety of a second romosozumab course.

METHODS

In this phase 2, dose-finding study, postmenopausal women with low bone mass (T-score ≤ - 2.0 and ≥ - 3.5) received romosozumab or placebo (month 0-24) followed by placebo or denosumab (month 24-36); participants then received a year of romosozumab (month 36-48).

RESULTS

Of 167 participants who entered the month 36-48 period, 35 had been initially randomized to romosozumab 210 mg monthly. In participants who received romosozumab 210 mg monthly followed by placebo, a second romosozumab course (n = 19) increased BMD by amounts similar to their initial treatment (month 0-12) at the lumbar spine (12.4%; 12.0%, respectively) and total hip (6.0%; 5.5%, respectively). Following denosumab, a second romosozumab course (n = 16) increased BMD at the lumbar spine (2.3%) and maintained BMD at the total hip. Safety profiles were similar between first and second romosozumab courses.

CONCLUSIONS

After 12 months off-treatment, a second romosozumab course again led to rapid and large BMD gains. Following denosumab, BMD gains with romosozumab were smaller than with initial treatment. No new safety findings were observed during the second course.

The risk of subsequent osteoporotic fractures is decreased in subjects experiencing fracture while on denosumab: results from the FREEDOM and FREEDOM Extension studies

This post-hoc analysis queried whether women experiencing fracture on denosumab indicates inadequate treatment response or whether the risk of subsequent fracture remains low with continuing denosumab. Results showed that denosumab decreases the risk of subsequent fracture and fracture sustained while on denosumab is not necessarily indicative of inadequate treatment response.

INTRODUCTION

This analysis assessed whether a fracture sustained during denosumab therapy indicates inadequate treatment response and if the risk of a subsequent fracture decreases with continuing denosumab treatment.

METHODS

In FREEDOM, a clinical trial to evaluate the efficacy and safety of denosumab, postmenopausal women with osteoporosis were randomized to placebo or denosumab for 3 years. In the 7-year FREEDOM Extension, all participants were allocated to receive denosumab. Here we compare subsequent osteoporotic fracture rates between denosumab-treated subjects during FREEDOM or the Extension and placebo-treated subjects in FREEDOM.

RESULTS

During FREEDOM, 438 placebo- and 272 denosumab-treated subjects had an osteoporotic fracture. Exposure-adjusted subject incidence per 100 subject-years was lower for denosumab (6.7) vs placebo (10.1). Combining all subjects on denosumab from FREEDOM and the Extension for up to 10 years (combined denosumab), 794 (13.7%) had an osteoporotic fracture while on denosumab. Of these, one or more subsequent fractures occurred in 144 (18.1%) subjects, with an exposure-adjusted incidence of 5.8 per 100 subject-years, similar to FREEDOM denosumab (6.7 per 100 subject-years) and lower than FREEDOM placebo (10.1 per 100 subject-years). Adjusting for prior fracture, the risk of having a subsequent on-study osteoporotic fracture was lower in the combined denosumab group vs placebo (hazard ratio [95% CI]: 0.59 [0.43-0.81]; P = 0.0012).

CONCLUSIONS

These data demonstrate that denosumab decreases the risk of subsequent fracture and a fracture sustained while on denosumab is not necessarily indicative of inadequate treatment response.

Recommendations for the conduct of economic evaluations in osteoporosis: outcomes of an experts' consensus meeting organized by the European Society for Clinical and Economic Aspects of Osteoporosis, Osteoarthritis and Musculoskeletal Diseases (ESCEO) and the US branch of the International Osteoporosis Foundation

Economic evaluations are increasingly used to assess the value of health interventions, but variable quality and heterogeneity limit the use of these evaluations by decision-makers. These recommendations provide guidance for the design, conduct, and reporting of economic evaluations in osteoporosis to improve their transparency, comparability, and methodologic standards.

INTRODUCTION

This paper aims to provide recommendations for the conduct of economic evaluations in osteoporosis in order to improve their transparency, comparability, and methodologic standards.

METHODS

A working group was convened by the European Society for Clinical and Economic Aspects of Osteoporosis and Osteoarthritis to make recommendations for the design, conduct, and reporting of economic evaluations in osteoporosis, to define an osteoporosis-specific reference case to serve a minimum standard for all economic analyses in osteoporosis, to discuss methodologic challenges and initiate a call for research. A literature review, a face-to-face meeting in New York City (including 11 experts), and a review/approval by a larger group of experts worldwide (including 23 experts in total) were conducted.

RESULTS

Recommendations on the type of economic evaluation, methods for economic evaluation, modeling aspects, base-case analysis and population, excess mortality, fracture costs and disutility, treatment characteristics, and model validation were provided. Recommendations for reporting economic evaluations in osteoporosis were also made and an osteoporosis-specific checklist was designed that includes items to report when performing an economic evaluation in osteoporosis. Further, 12 minimum criteria for economic evaluations in osteoporosis were identified and 12 methodologic challenges and need for further research were discussed.

CONCLUSION

While the working group acknowledges challenges and the need for further research, these recommendations are intended to supplement general and national guidelines for economic evaluations, improve transparency, quality, and comparability of economic evaluations in osteoporosis, and maintain methodologic standards to increase their use by decision-makers.

Bone management in hematologic stem cell transplant recipients

Autologous and allogeneic hematopoietic stem cell transplantation (HSCT) is the treatment of choice for patients with some malignant and non-malignant hematological diseases. Advances in transplantation techniques and supportive care measures have substantially increased the number of long-term HSCT survivors. This has led to an increasing patient population suffering from the late effects of HSCT, of which, bone loss and its consequent fragility fractures lead to substantial morbidity. Altered bone health, with consequent fragility fractures, and chronic graft-versus-host disease (GVHD) are factors affecting long-term quality of life after HSCT. Hypogonadism, HSCT preparative regimens, nutritional factors, and glucocorticoids all contribute to accelerated bone loss and increased fracture risk. Management strategies should include bone mineral density examination, evaluation of clinical risk factors, and general dietary and physical activity measures. Evidence has accumulated permitting recommendations for more attentiveness to evaluation and monitoring of bone health, with appropriate application of osteoporosis pharmacotherapies to patients at increased risk of bone loss and fracture.

Diagnosis and management of bone fragility in diabetes: an emerging challenge

Fragility fractures are increasingly recognized as a complication of both type 1 and type 2 diabetes, with fracture risk that increases with disease duration and poor glycemic control. Yet the identification and management of fracture risk in these patients remains challenging. This review explores the clinical characteristics of bone fragility in adults with diabetes and highlights recent studies that have evaluated bone mineral density (BMD), bone microstructure and material properties, biochemical markers, and fracture prediction algorithms (i.e., FRAX) in these patients. It further reviews the impact of diabetes drugs on bone as well as the efficacy of osteoporosis treatments in this population. We finally propose an algorithm for the identification and management of diabetic patients at increased fracture risk.

Build better bones with exercise (B3E pilot trial): results of a feasibility study of a multicenter randomized controlled trial of 12 months of home exercise in older women with vertebral fracture

We pilot-tested a trial of home exercise on individuals with osteoporosis and spine fracture. Our target enrollment was met, though it took longer than expected. Participants stayed in the study and completed the exercise program with no safety concerns. Future trials should expand the inclusion criteria and consider other changes.

PURPOSE

Osteoporotic fragility fractures create a substantial human and economic burden. There have been calls for a large randomized controlled trial examining the effect of exercise on fracture incidence. The B3E pilot trial was designed to evaluate the feasibility of a large trial examining the effects of home exercise on individuals at high risk of fracture.

METHODS

Community-dwelling women ≥ 65 years with radiographically confirmed vertebral compression fractures were recruited at seven sites in Canada and Australia. We randomized participants in a 1:1 ratio to a 12-month home exercise program or equal attention control group, both delivered by a physiotherapist (PT). Participants received six PT home visits in addition to monthly phone calls from the PT and a blinded research assistant. The primary feasibility outcomes of the study were recruitment rate (20 per site in 1 year), retention rate (75% completion), and intervention adherence rate (60% of weeks meeting exercise goals). Secondary outcomes included falls, fractures and adverse events.

RESULTS

One hundred forty-one participants were recruited; an average of 20 per site, though most sites took longer than anticipated. Retention and adherence met the criteria for success: 92% of participants completed the study; average adherence was 66%. The intervention group did not differ significantly in the number of falls (IRR 0.97, 95% CI 0.58 to 1.63) or fragility fractures (OR 1.11, 95% CI 0.60 to 2.05) compared to the control group. There were 18 serious adverse events in the intervention group and 12 in the control group.

CONCLUSION

An RCT of home exercise in women with vertebral fractures is feasible but recruitment was a challenge. Suggestions are made for the conduct of future trials.

Persistence at 24 months with denosumab among postmenopausal women with osteoporosis: results of a prospective cohort study

Persistence with prescribed medications for chronic diseases is important; however, persistence with osteoporosis treatments is historically poor. In this prospective cohort study of postmenopausal women treated for osteoporosis in real-world clinical practice settings in the USA and Canada, 24-month persistence with denosumab was 58%.

PURPOSE

Patients who persist with their prescribed osteoporosis treatment have increased bone mineral density (BMD) and reduced risk of fracture. Twelve-month persistence with denosumab in routine clinical practice is as high as 95%, but there are limited data on longer-term persistence with denosumab in this setting.

METHODS

This single-arm, prospective, cohort study evaluated 24-month persistence with denosumab administered every 6 months in postmenopausal women receiving treatment for osteoporosis in real-world clinical practice in the USA and Canada. Endpoints and analyses included the percentage of patients who persist with denosumab at 24 months (greater than or equal to four injections with a gap between injections of no more than 6 months plus 8 weeks), the total number of injections received by each patient, changes in BMD in persistent patients, and the incidence of serious adverse events (SAEs) and fractures.

RESULTS

Among 935 enrolled patients, 24-month persistence was 58% (50% in US patients and 75% in Canadian patients). A majority of patients received at least four injections over the observation period (62% of US patients and 81% of Canadian patients). Among patients who were persistent at 24 months and who had a baseline, 12-month, and 24-month DXA scan, mean BMD increased from baseline to 24 months by 7.8% at the lumbar spine and 2.1% at the femoral neck. SAEs and fractures were reported for 122 (13.0%) patients and 54 (5.8%) patients, respectively.

CONCLUSIONS

Persistence with denosumab for 24 months yields improvement in BMD among postmenopausal women with osteoporosis treated in routine clinical practice in the USA and Canada.

Vertebral Fractures: Clinical Importance and Management

Vertebral fractures are common and can result in acute and chronic pain, decreases in quality of life, and diminished lifespan. The identification of vertebral fractures is important because they are robust predictors of future fractures. The majority of vertebral fractures do not come to clinical attention. Numerous modalities exist for visualizing suspected vertebral fracture. Although differing definitions of vertebral fracture may present challenges in comparing data between different investigations, at least 1 in 5 men and women aged >50 years have one or more vertebral fractures. There is clinical guidance to target spine imaging to individuals with a high probability of vertebral fracture. Radiology reports of vertebral fracture need to clearly state that the patient has a "fracture," with further pertinent details such as the number, recency, and severity of vertebral fracture, each of which is associated with risk of future fractures. Patients with vertebral fracture should be considered for antifracture therapy. Physical and pharmacologic modalities of pain control and exercises or physiotherapy to maintain spinal movement and strength are important components in the care of vertebral fracture patients.

The effect of 8 or 5 years of denosumab treatment in postmenopausal women with osteoporosis: results from the FREEDOM Extension study

The FREEDOM study and its Extension provide long-term information about the effects of denosumab for the treatment of postmenopausal osteoporosis. Treatment for up to 8 years was associated with persistent reduction of bone turnover, continued increases in bone mineral density, low fracture incidence, and a favorable benefit/risk profile.

INTRODUCTION

This study aims to report the results through year 5 of the FREEDOM Extension study, representing up to 8 years of continued denosumab treatment in postmenopausal women with osteoporosis.

METHODS

Women who completed the 3-year FREEDOM study were eligible to enter the 7-year open-label FREEDOM Extension in which all participants are scheduled to receive denosumab, since placebo assignment was discontinued for ethical reasons. A total of 4550 women enrolled in the Extension (2343 long-term; 2207 cross-over). In this analysis, women in the long-term and cross-over groups received denosumab for up to 8 and 5 years, respectively.

RESULTS

Throughout the Extension, sustained reduction of bone turnover markers (BTMs) was observed in both groups. In the long-term group, mean bone mineral density (BMD) continued to increase significantly at each time point measured, for cumulative 8-year gains of 18.4 and 8.3 % at the lumbar spine and total hip, respectively. In the cross-over group, mean BMD increased significantly from the Extension baseline for 5-year cumulative gains of 13.1 and 6.2 % at the lumbar spine and total hip, respectively. The yearly incidence of new vertebral and nonvertebral fractures remained low in both groups. The incidence of adverse and serious adverse events did not increase over time. Through Extension year 5, eight events of osteonecrosis of the jaw and two events of atypical femoral fracture were confirmed.

CONCLUSIONS

Denosumab treatment for up to 8 years was associated with persistent reductions of BTMs, continued BMD gains, low fracture incidence, and a consistent safety profile.

Further reductions in nonvertebral fracture rate with long-term denosumab treatment in the FREEDOM open-label extension and influence of hip bone mineral density after 3 years

Limited data exist on the efficacy of long-term therapies for osteoporosis. In osteoporotic postmenopausal women receiving denosumab for 7 years, nonvertebral fracture rates significantly decreased in years 4-7 versus years 1-3. This is the first demonstration of a further benefit on fracture outcomes with long-term therapy for osteoporosis.

INTRODUCTION

This study aimed to evaluate whether denosumab treatment continued beyond 3 years is associated with a further reduction in nonvertebral fracture rates.

METHODS

Participants who completed the 3-year placebo-controlled Fracture REduction Evaluation of Denosumab in Osteoporosis every 6 Months (FREEDOM) study were invited to participate in an open-label extension. The present analysis includes 4,074 postmenopausal women with osteoporosis (n = 2,343 long-term; n = 1,731 cross-over) who enrolled in the extension, missed ≤1 dose during their first 3 years of denosumab treatment, and continued into the fourth year of treatment. Comparison of nonvertebral fracture rates during years 1-3 of denosumab with that of the fourth year and with the rate during years 4-7 was evaluated.

RESULTS

For the combined group, the nonvertebral fracture rate per 100 participant-years was 2.15 for the first 3 years of denosumab treatment (referent) and 1.36 in the fourth year (rate ratio [RR] = 0.64; 95 % confidence interval (CI) = 0.48 to 0.85, p = 0.003). Comparable findings were observed in the groups separately and when nonvertebral fracture rates during years 1-3 were compared to years 4-7 in the long-term group (RR = 0.79; 95 % CI = 0.62 to 1.00, p = 0.046). Fracture rate reductions in year 4 were most prominent in subjects with persisting low hip bone mineral density (BMD).

CONCLUSIONS

Denosumab treatment beyond 3 years was associated with a further reduction in nonvertebral fracture rate that persisted through 7 years of continuous denosumab administration. The degree to which denosumab further reduces nonvertebral fracture risk appears influenced by the hip bone density achieved with initial therapy.

Treatment with denosumab reduces secondary fracture risk in women with postmenopausal osteoporosis

OBJECTIVES

A history of prior fracture is one of the strongest predictors of a future fragility fracture. In FREEDOM, denosumab significantly reduced the risk of new vertebral, non-vertebral, and hip fractures. We carried out a post-hoc analysis of FREEDOM to characterize the efficacy of denosumab in preventing secondary fragility fractures in subjects with a prior fracture.

METHODS

A total of 7808 women aged 60-90 years with a bone mineral density T-score of less than - 2.5 but not less than - 4.0 at either the lumbar spine or total hip were randomized to subcutaneous denosumab 60 mg or placebo every 6 months for 36 months. The anti-fracture efficacy of denosumab was analyzed by prior fracture status, to assess secondary fragility fracture, and by subject age, prior fracture site and history of prior osteoporosis medication use.

RESULTS

A prior fragility fracture was reported for 45% of the overall study population. Compared with placebo, denosumab significantly reduced the risk of a secondary fragility fracture by 39% (incidence, 17.3% vs. 10.5%; p < 0.0001). Similar results were observed regardless of age or prior fracture site. In the overall population, denosumab significantly reduced the risk of a fragility fracture by 40% (13.3% vs. 8.0%; p < 0.0001), with similar results observed regardless of history of prior osteoporotic medication use.

CONCLUSIONS

Denosumab reduced the risk of fragility fractures to a similar degree in all risk subgroups examined, including those with prior fragility fractures. Identifying and treating high-risk individuals could help to close the current care gap in secondary fracture prevention.

A case report of osteomalacia unmasking primary biliary cirrhosis

Osteomalacia, a metabolic bone disease characterized by the inability to mineralize new osteoid, can be caused by vitamin D deficiency. We report a patient with symptomatic, biochemical, and imaging evidence of osteomalacia due to vitamin D deficiency, who as a result of work up for bone disease was diagnosed with early primary biliary cirrhosis. Osteomalacia was treated with high-dose vitamin D and serial bone density scans showed evidence of increasing bone mineral density suggesting osteoid mineralization in response to treatment. The diagnosis of cholestatic liver disease should be considered in all patients presenting with osteomalacia due to vitamin D deficiency, particularly if other cholestatic liver enzymes are elevated in addition to alkaline phosphatase.

Persistence at 12 months with denosumab in postmenopausal women with osteoporosis: interim results from a prospective observational study

To determine persistence with subcutaneous denosumab every 6 months in women being treated for osteoporosis, we conducted a single-arm prospective, observational study in the United States and Canada. Among 935 patients enrolled, 12-month persistence was 82%, with 66 patients (7%) reporting serious adverse events and 19 patients (2%) reporting fractures.

INTRODUCTION

Increased persistence with osteoporosis therapy is associated with reduced fracture risk. Denosumab reduced fracture risk in clinical trials; persistence in community settings is undetermined. This study evaluates persistence with denosumab in community practice in the United States (US) and Canada.

METHODS

In a 24-month multicenter, prospective, single-arm, observational study, women being treated for osteoporosis were enrolled ≤4 weeks after the first subcutaneous injection of denosumab. For this 12-month prespecified interim analysis, endpoints include persistence (one injection at study entry and another within 6 months + 8 weeks), attributes associated with persistence (univariate analysis), and serious adverse events (SAEs).

RESULTS

Among 935 patients (mean age 71 years), mean baseline T-scores were -2.18 (femoral neck) and -2.00 (lumbar spine); 50% of patients had experienced osteoporotic fracture(s). At 12 months, 82 % of patients were persistent with denosumab. Baseline factors significantly (p < 0.05) associated with higher persistence included use of osteoporosis medications >5 years previously, lumbar spine T-score > -2.5, and treatment by female physicians (US). Lower persistence was associated (p < 0.05) with psychiatric diagnoses including depression, southern US residence, being divorced, separated, or widowed (US), and prior hip fracture (Canada). SAEs were reported in 66 patients (7%); no SAEs of osteonecrosis of the jaw, atypical femoral fracture, fracture healing complications, hypocalcemia, eczema, or hypersensitivity were reported. Nineteen patients (2%) reported osteoporotic fractures.

CONCLUSIONS

The 12-month persistence observed in this single-arm open-label study of US and Canadian community practice extends the evidence regarding denosumab's potential role in reducing fracture risk in postmenopausal women with osteoporosis.

Arzoxifene versus raloxifene: effect on bone and safety parameters in postmenopausal women with osteoporosis

Arzoxifene increased bone mineral density and decreased bone turnover to a significantly greater extent than raloxifene. The hot flush incidence was lower with arzoxifene than raloxifene.

INTRODUCTION

To assess the effect of arzoxifene versus raloxifene on change in lumbar spine (LS) bone mineral density (BMD) in postmenopausal women with osteoporosis.

METHODS

In this 12-month study (NEXT trial), participants were randomly assigned to arzoxifene 20 mg/day (N = 158) or raloxifene 60 mg/day (N = 162). All received daily calcium and vitamin D. Change in LS BMD was assessed by DXA. Secondary objectives included assessment of femoral neck (FN) and total hip BMD, serum bone turnover markers, and safety.

RESULTS

Treatment groups were similar at baseline (mean age 63 years, mean LS BMD T-score -2.9). At 12 months, the increase in LS BMD with arzoxifene was greater than with raloxifene (+2.75% vs. +1.66%), as was FN and total hip BMD (P < 0.05). For LS and FN, this effect was also evident at 6 months. Arzoxifene reduced bone turnover to a greater extent than raloxifene at 3, 6, and 12 months (P < 0.05). The proportion of women reporting ≥ 1 adverse event did not differ between treatment groups, nor did vaginal bleeding. No cases of endometrial polyps, hyperplasia, or cancer were reported. Nasopharyngitis and bronchitis were reported more frequently with arzoxifene versus raloxifene (10.1% vs. 2.5%, and 5.1% vs. 0%, respectively) and new/worsening hot flushes were reported less frequently with arzoxifene (7.0% vs. 16.7%) (P < 0.05).

CONCLUSIONS

Arzoxifene increased BMD and suppressed bone turnover to a greater extent than raloxifene and resulted in a lower incidence of new/worsening hot flushes. Based on subsequent findings from a fracture outcome study, this difference did not translate into improved fracture efficacy.

Sustained efficacy and safety of bazedoxifene in preventing fractures in postmenopausal women with osteoporosis: results of a 5-year, randomized, placebo-controlled study

In this 2-year extension of a 3-year study, bazedoxifene showed sustained efficacy in preventing new vertebral fractures in postmenopausal women with osteoporosis and in preventing non-vertebral fractures in higher-risk women. Bazedoxifene significantly increased bone mineral density and reduced bone turnover versus placebo and was generally safe and well tolerated.

INTRODUCTION

This study evaluated the efficacy and safety of bazedoxifene for the treatment of postmenopausal osteoporosis over 5 years.

METHODS

A total of 4,216 postmenopausal women with osteoporosis were enrolled in this 2-year extension of a 3-year, randomized, double-blind, placebo-controlled, phase 3 trial. In the core study (N = 7,492), subjects received bazedoxifene 20 or 40 mg/day, raloxifene 60 mg/day, or placebo. The raloxifene arm was discontinued after 3 years; subjects receiving bazedoxifene 40 mg were transitioned to bazedoxifene 20 mg after 4 years. Five-year findings are reported for bazedoxifene 20 and 40/20 mg and placebo. Endpoints included incidence of new vertebral fractures (primary) and non-vertebral fractures, and changes in bone mineral density (BMD) and bone turnover markers.

RESULTS

At 5 years, the incidence of new vertebral fractures in the intent-to-treat population was significantly lower with bazedoxifene 20 mg (4.5%) and 40/20 mg (3.9%) versus placebo (6.8%; P < 0.05), with relative risk reductions of 35% and 40%, respectively. Non-vertebral fracture incidence was similar among groups. In a subgroup of higher-risk women (n = 1,324; femoral neck T-score ≤-3.0 and/or ≥ 1 moderate or severe or ≥ 2 mild vertebral fracture[s]), bazedoxifene 20 mg reduced non-vertebral fracture risk versus placebo (37%; P = 0.06); combined data for bazedoxifene 20 and 40/20 mg reached statistical significance (34% reduction; P < 0.05). Bazedoxifene significantly increased BMD and reduced bone turnover versus placebo (P < 0.05) and was generally safe and well tolerated.

CONCLUSIONS

The findings support a sustained anti-fracture effect of bazedoxifene on new vertebral fractures in postmenopausal osteoporotic women and on non-vertebral fractures in the higher-risk subgroup of women.

Final results of the DAPS (Denosumab Adherence Preference Satisfaction) study: a 24-month, randomized, crossover comparison with alendronate in postmenopausal women

The final analysis of this 2-year, randomized, crossover study showed that postmenopausal women with osteoporosis were more adherent, compliant, and persistent with subcutaneous denosumab injections every 6 months than with once-weekly alendronate tablets. After receiving both treatments, women reported greater satisfaction with injectable denosumab and preferred it over oral alendronate.

INTRODUCTION

Osteoporosis patients who are non-compliant or non-persistent with therapy may have suboptimal clinical outcomes. This 2-year, randomized, open-label, crossover study compared treatment adherence between subcutaneous denosumab, 60 mg every 6 months, and oral alendronate, 70 mg once weekly.

METHODS

Postmenopausal women at 25 centers in the USA and Canada with bone mineral density T-scores -4.0 to -2.0 and no prior bisphosphonate use received alendronate then denosumab, or denosumab then alendronate, over successive 12-month periods. Adherence required both compliance (denosumab injections 6 months apart or ≥ 80% of alendronate tablets) and persistence (both denosumab injections or ≥ 2 alendronate doses in the last month and completion of the treatment period).

RESULTS

Of the 250 women enrolled (124 alendronate, 126 denosumab), 221 entered the second year (106 denosumab, 115 alendronate). Denosumab was associated with less non-adherence than alendronate (first year, 11.9% vs 23.4%; second year, 7.5% vs 36.5%). Risk ratios for non-adherence, non-compliance, and non-persistence favored denosumab in both years (p < 0.05). Of 198 subjects expressing treatment preference, 183 (92.4%) preferred the injections over the oral therapy. BMD improved further when subjects received denosumab after alendronate and remained stable when they received alendronate after denosumab.

CONCLUSION

Based on the final results of this crossover study after women had received each treatment for up to 1 year, postmenopausal women with osteoporosis were more adherent, compliant, and persistent with subcutaneous denosumab injections every 6 months than with once-weekly alendronate tablets and reported increased treatment preference and satisfaction with injectable denosumab over oral alendronate.

Adherence, preference, and satisfaction of postmenopausal women taking denosumab or alendronate

In this study, 250 women with osteoporosis were randomized to 12 months with subcutaneous denosumab 60 mg every 6 months or oral alendronate 70 mg once weekly, then crossed over to the other treatment. The primary endpoint, treatment adherence at 12 months, was 76.6% for alendronate and 87.3% for denosumab.

INTRODUCTION

The purpose of this study is to evaluate treatment adherence with subcutaneous denosumab 60 mg every 6 months or oral alendronate 70 mg once weekly.

METHODS

In this multicenter, randomized, open-label, 2-year, crossover study, 250 postmenopausal women with low bone mineral density received denosumab or alendronate for 12 months, then the other treatment for 12 months. The alendronate bottle had a medication event monitoring system cap to monitor administration dates. Definitions were as follows: compliance, receiving both denosumab doses 6 (± 1) months apart or 80-100% of alendronate doses; persistence, receiving both denosumab doses and completing the month 12 visit within the visit window or ≥ 2 alendronate doses in the final month; adherence, achieving both compliance and persistence. This report includes data from the first 12 months.

RESULTS

The primary study endpoint, adherence in the first 12 months, was 76.6% (95/124) for alendronate and 87.3% (110/126) for denosumab. Risk ratios for denosumab compared with alendronate at 12 months were 0.58 (p = 0.043) for non-adherence, 0.48 (p = 0.014) for non-compliance, and 0.54 (p = 0.049) for non-persistence. Subject ratings for treatment necessity, preference, and satisfaction were significantly greater for denosumab and ratings for treatment bother were significantly greater for alendronate. Adverse events were reported by 64.1% of alendronate-treated subjects and 72.0% of denosumab-treated subjects (p = 0.403). The most common adverse events were arthralgia, back pain, pain in extremity, cough, and headache (each in <10% of subjects in each group).

CONCLUSIONS

Significantly greater treatment adherence was observed for subcutaneous administration of denosumab every 6 months than for oral alendronate once weekly.

Population-based Canadian hip fracture rates with international comparisons

SUMMARY

We identified hospitalizations throughout Canada during 2000-2005 in which the most responsible diagnosis was a proximal femoral fracture. Use of the US fracture risk assessment tool (FRAX) would be inappropriate for Canada as it would overestimate fracture risk in Canadian women and older men.

INTRODUCTION

It is recommended that the WHO fracture risk assessment tool should be calibrated to the target population.

METHODS

We identified hospitalizations for women and men throughout Canada during the study period 2000-2005 in which the most responsible diagnosis was a proximal femoral fracture (147,982 hip fractures). Age-standardized hip fracture rates were compared between Canadian provinces, and national rates were compared with those reported for the USA and Germany.

RESULTS

There were relatively small differences in hip fracture rates between provinces, and most did not differ appreciably from the Canadian average. Hip fracture rates for women in Canada in 2001 were substantially lower than in the USA (population-weighted rate ratio 0.70) and were also lower than in Germany for 2004 (population-weighted rate ratio 0.74).

CONCLUSIONS

Overall hip fracture rates for Canadian women were found to be substantially lower than those for the USA and Germany. This study underscores the importance of assessing country-specific fracture patterns prior to adopting an existing FRAX tool.

Preference and satisfaction with a 6-month subcutaneous injection versus a weekly tablet for treatment of low bone mass

The Preference and Satisfaction Questionnaire (PSQ) compares patient preference and satisfaction between a 6-month subcutaneous injection and weekly oral tablet for treatment of bone loss. Patients preferred and were more satisfied with a treatment that was administered less frequently, suggesting the acceptability of the 6-month injection for treatment of bone loss.

INTRODUCTION

The PSQ compares patient preference and satisfaction between a 6-month subcutaneous injection and a weekly oral tablet for treatment of bone loss.

METHODS

Postmenopausal women with low bone mass who enrolled in two separate randomized phase 3 double-blind, double-dummy studies received a 6-month subcutaneous denosumab injection (60 mg) plus a weekly oral placebo or a weekly alendronate tablet (70 mg) plus a 6-month subcutaneous placebo injection. After 12 months, patients completed the PSQ to rate their preference, satisfaction, and degree of bother with each regimen.

RESULTS

Most enrolled patients (1,583 out of 1,693; 93.5%) answered >or=1 item of the PSQ. Significantly more patients preferred and were more satisfied with the 6-month injection versus the weekly tablet (P < 0.001). More patients reported no bother with the 6-month injection (90%) than the weekly tablet (62%).

CONCLUSION

Patients preferred, were more satisfied, and less bothered with a 6-month injection regimen for osteoporosis.

Risedronate dosing before breakfast compared with dosing later in the day in women with postmenopausal osteoporosis

Two studies in postmenopausal women with osteoporosis provide information about the efficacy and safety of dosing oral risedronate 5 mg daily at a time other than before breakfast (i.e., 2 h before and 2 h after any food and drink other than plain water). A significant increase in lumbar spine BMD was observed for both treatment regimens in the two studies. However, smaller increases in lumbar spine BMD were observed with flexible dosing versus before-breakfast dosing. Geographic region, compliance, and consistency of dosing time appear to affect the amount of increase in BMD observed with flexible dosing.

INTRODUCTION

Two studies in postmenopausal women with osteoporosis provide additional information about the efficacy and safety of dosing oral risedronate 5 mg daily at a time other than before breakfast (i.e., 2 h before and 2 h after any food and drink other than plain water).

METHODS

One study, flexible dosing, was a 6-month North American study in 730 patients randomized to before-breakfast dosing or flexible dosing later in the day. A second study, IMPACT, was a large (N = 2382), 1-year multinational study in patients that chose their dosing regimen (before breakfast or later in the day). These studies were used to examine the bone mineral density (BMD) response with different dosing regimens.

RESULTS

A significant increase in lumbar spine BMD was observed for both treatment regimens in the two studies. However, in both studies, the flexible dosing group had a smaller increase from baseline compared to the before-breakfast regimen (ratio of flexible dosing to before breakfast: flexible dosing study, 0.52; IMPACT study, 0.75). In addition, a relationship between geographic region and BMD response was observed with flexible dosing in both studies. Patients in the flexible dosing group who had greater dosing compliance (based on the number of times the bottle was opened) and consistency of dosing time (bottle opened within a 1.5-h window) had a greater increase in lumbar spine BMD.

CONCLUSION

Results of these two studies demonstrate that overall flexible dosing of risedronate leads to smaller BMD gains compared to before-breakfast dosing. This result may be due to poorer adherence to the flexible dosing instructions that may be more pronounced in patients in certain geographic regions. If patients cannot abide by before-breakfast dosing and flexible dosing is an approved option, one can expect suboptimal BMD results with flexible dosing.

Monitoring strontium ranelate therapy in patients with osteoporosis

PURPOSE

The purpose of this study was to review the monitoring of strontium ranelate osteoporosis therapy.

METHODS

The method used in this study was comprehensive literature review with clinical perspectives.

RESULTS

Changes in bone turnover markers (BTM) or bone mineral density (BMD) have been documented in osteoporosis clinical trials. However, neither BMD nor BTM changes fully explain the observed fracture risk reduction in treated patients. If changes in BMD or BTM on therapy would be easily discernable in individual patients, and were strongly associated with fracture risk reduction, monitoring individuals would be more useful. BMD changes in patients on strontium ranelate are of a greater magnitude and hence can be easily determined in an individual patient. In addition, there exists a better correlation between fracture risk reduction and increases in BMD.

CONCLUSIONS

The strong correlation between measured BMD increases and fracture risk reduction in patients on strontium ranelate therapy will be of clinical benefit to physicians wishing to evaluate both treatment persistence and fracture risk reduction.

Special report on the 2007 adult and pediatric Position Development Conferences of the International Society for Clinical Densitometry

The International Society for Clinical Densitometry (ISCD) conducts Position Development Conferences (PDCs) for the purpose of establishing standards and guidelines in the field of bone densitometry. Topics for consideration are selected according to clinical relevance, a perceived need for standardization, and the likelihood of achieving agreement. Questions regarding nomenclature, indications, acquisition, analysis, quality control, interpretation, and reporting of bone density tests for each topic area are assigned to task forces for a comprehensive review of the scientific literature. The findings of the review and recommendations are then presented to an international panel of experts at the PDC. The expert panel votes on potential Official Positions for appropriateness, necessity, quality of the evidence, strength of the recommendation, and applicability (worldwide or variable according to local requirements). Recommendations that are approved by the ISCD Board of Directors become Official Positions. The first Pediatric PDC was 20-21 June 2007 in Montreal, QC, Canada. The most recent Adult PDC was held 20-22 July 2007, in Lansdowne, VA, USA. This Special Report summarizes the methodology of the ISCD PDCs and presents selected Official Positions of general interest.

Pharmaceutical care and community pharmacists' understanding of bisphosphonate dosing information1

OBJECTIVES

To evaluate pharmacists' knowledge of approved dosing information for cyclic etidronate, alendronate and risedronate in the treatment of postmenopausal osteoporosis; and to assess its relationship to demographic and pharmaceutical care factors.

DESIGN

Fax-back questionnaire to evaluate pharmacists' knowledge of approved bisphosphonate dosing information and their involvement in pharmaceutical/patient care activities through independent indices.

SETTING

Community pharmacies in both urban and rural settings in British Columbia.

PARTICIPANTS

Pharmacies surveyed with 22% response rate (163 pharmacists), 47% male and 54% owners/managers. Most were independent (31%) or volunteer chain (28%) pharmacies.

MEASUREMENTS AND MAIN RESULTS

Mean bisphosphonate dosing knowledge score was 76 +/- 11% (mean +/- SD). Mean scores (+/-SD) for questions pertaining to alendronate (92 +/- 13%) were higher than risedronate (81 +/- 26%) and etidronate (48 +/- 19). Pharmacists were least familiar with approved dosing instructions regarding the lack of need to remain upright after etidronate dosing, spacing out of etidronate from food/antacids/calcium/vitamins, and whether risedronate may be taken at bedtime. Factors found to affect pharmacists' bisphosphonate knowledge scores included employment in higher volume pharmacies and greater number of years in practice. Pharmacists in the upper tertile of pharmaceutical care index scores had similar bisphosphonate knowledge scores to those delivering less pharmaceutical care. Pharmacist gender, being owner/manager, and continuing education hours were not significantly associated with higher knowledge or pharmaceutical care scores.

CONCLUSIONS

There is a wide range of knowledge of bisphosphonate dosing and delivery of pharmaceutical care amongst community pharmacists surveyed. Given the importance of proper bisphosphonate dosing to optimize drug absorption and to minimize toxicity, pharmacist education should be a priority.

Special report on the official positions of the International Society for Clinical Densitometry

The International Society for Clinical Densitometry (ISCD) periodically holds Position Development Conferences (PDCs) for the purpose of establishing standards and guidelines for indications, acquisition, and interpretation of bone density tests. Topics are selected for consideration by the ISCD Scientific Advisory Committee, reviewed by scientific working groups, and presented to an international panel of experts. Topic categories addressed to date include indications for bone density testing, selection of reference databases for T-scores and Z-scores, clinical applications for central and peripheral bone densitometry, serial bone density testing, instrument precision assessment, phantom scanning and calibration testing, requirements for a bone density report, nomenclature, and diagnosis of osteoporosis in postmenopausal women, premenopausal women, men, and children. Following an open session for public comment and discussion, the panel convenes for consideration of each topic and makes recommendations for positions to the ISCD Board of Directors. Recommendations that are accepted become the Official Positions of the ISCD. This Special Report summarizes the methodology of the ISCD PDCs and presents selected Official Positions of general interest.

An investigation of the predictors of bone mineral density and response to therapy with alendronate in osteoporotic men

Male osteoporosis is an important disease, with 25-30% of all hip fractures occurring in men. In a recent randomized, placebo-controlled study of osteoporotic males, alendronate 10 mg daily for 2 yr led to significant increments in bone mineral density (BMD), of a similar magnitude to those observed in postmenopausal women. In this study, specimens collected at intervals during the recent trial of alendronate in male osteoporosis, from 197 of the original 241 participants, were assayed for testosterone, estradiol, IGF-I, IGF binding protein 3 (IGFBP-3), bone-specific alkaline phosphatase [BSAP (serum)], and N-telopeptide of type I collagen corrected for creatinine [NTx (urine)]. Together with fracture and densitometry data from the original study, relationships were examined between BMD and serum IGF-I, IGFBP-3, testosterone, estradiol, BSAP, and urine NTx, both at baseline and during treatment with alendronate, to gain possible insights into the pathogenesis of male osteoporosis. Statistically significant (P <or= 0.05) associations were documented, at baseline, between the presence of vertebral fracture and each of serum IGF-I, serum IGFBP-3, serum free testosterone, total spine BMD, and total body BMD. No statistically significant correlations were observed between any of the baseline variables (IGF-I, IGFBP-3, estradiol, testosterone, and presence of vertebral fracture) and the BMD response to alendronate at any site. In a multivariate analysis, used to identify possible combinations of factors capable of predicting baseline BMD or response to alendronate, statistically significant (P <or= 0.01) relationships were seen, at baseline, between BMD and body mass index, age, and prior fracture. However, no statistically significant relationships were seen between any of the baseline variables (age, body mass index, testosterone, estradiol, IGF-I, IGFBP-3, and prior fracture) and change in BMD at any site. These data suggest that among men with osteoporosis it is not possible to identify patients who would be particularly good candidates for therapy with alendronate on the basis of biochemical or hormonal markers. Alendronate therapy appears to benefit osteoporotic males equally, irrespective of baseline serum testosterone, estradiol, IGF-I, or markers of bone turnover.

Hadju-Cheney syndrome: response to therapy with bisphosphonates in two patients

Hadju-Cheney syndrome is characterized by short stature, distinctive facies, and a slowly progressive skeletal dysplasia including acro-osteolysis. Autosomal dominant inheritance is typical, but the genetic defect and molecular pathogenesis of the syndrome are unknown. Osteoporosis with atraumatic fracture is a frequent finding, and previous studies have documented biochemical and morphometric evidence of high bone turnover. Here, we report the clinical details and response to therapy with bisphosphonates in two patients (mother and son) with Hadju-Cheney syndrome and postulate that osteoclast-mediated bone resorption is important in the generalized osteoporosis commonly associated with this condition.

The efficacy and tolerability of risedronate once a week for the treatment of postmenopausal osteoporosis

This study evaluated the efficacy and tolerability of risedronate once a week (35 mg and 50 mg) compared with risedronate 5 mg once daily in women with osteoporosis. We conducted a randomized, double-blind, active-controlled, 2-year study; the primary efficacy assessment was performed after 1 year. Subjects were women aged 50 years or older who had been postmenopausal for at least 5 years, with either a bone mineral density (BMD) T-score of -2.5 or lower (lumbar spine or proximal femur) or a T-score lower than -2 and at least one prevalent vertebral fracture. Subjects received risedronate 5 mg once daily, 35 mg once a week or 50 mg once a week. All subjects also received 1 g daily of elemental calcium supplementation and supplemental vitamin D if the baseline serum levels were low. The primary efficacy measure was percent change in lumbar spine BMD at 12 months. A total of 1,456 women were randomized and received medication; 1,209 (83%) women completed 12 months. The mean percent change (SE) in lumbar spine BMD after 12 months was 4.0% (0.2%) in the 5 mg daily group, 3.9% (0.2%) in the 35 mg group, and 4.2% (0.2%) in the 50 mg group; each once-a-week treatment was determined to be as effective as the daily treatment. Outcomes of the secondary efficacy measurements and safety assessments were also similar in all 3 groups after 12 months. Risedronate 35 mg and 50 mg once a week provide the same efficacy and safety as the daily 5 mg regimen; therefore, the lower dose, 35 mg once a week, is considered optimal for women with postmenopausal osteoporosis who desire a once-a-week regimen.

Use of phalangeal bone mineral density and multi-site speed of sound conduction to monitor therapy with alendronate in postmenopausal women

In women with postmenopausal osteoporosis (PMO), response to therapy with bisphosphonates is conventionally monitored using central-site (hip and spine) bone mineral density (BMD), but more convenient alternatives are desirable. During a randomized parallel-group study of the efficacy of once-weekly (80 mg vs 160 mg) oral alendronate in the treatment of PMO, 81 women (mean age 70.2 years +/- 4.6 SD) had BMD measurements of total hip (TH) and lumbar spine (LS) (L1-L4, Hologic); and of the middle phalanx of the middle digit of the non-dominant hand (accuDXA) at baseline and after 6 and 12 months of therapy with alendronate. At the same timepoints, subjects also had measurements of speed of sound (SOS) through bone at four sites (distal 1/3 radius, proximal phalanx of the third finger, midshaft of the tibia and fifth metatarsal) using the Sunlight Omnisense Ultrasound Bone Sonometer. Data from both patient groups were pooled for this analysis. Mean TH BMD at baseline was 0.705 g/cm2 +/- 0.093 (SD) and increased by 1.7% +/- 2.3% and 2.5% +/- 2.3% at 6 and 12 months respectively (p = 0.09 and p<0.0001). Mean LS BMD at baseline was 0.718 +/- 0.076 g/cm2 and increased by 3.9% +/- 3.6% and 6.1% +/- 3.5% at 6 and 12 months respectively (both p<0.0001). There was no statistically significant change from baseline in mean BMD by accuDXA at either 6 or 12 months. The only statistically significant changes in SOS were at the radius (decrease in SOS at 12 months, p= 0.04) and tibia (increase at 6 months, p<0.01, but no change between baseline and 12 months). Baseline correlation coefficients between accuDXA and LS and TH DXA were 0.22 (p = 0.05) and 0.27 (p = 0.02) respectively. Correlation coefficients between SOS and LS DXA ranged from 0.05 to 0.22; and between SOS and TH DXA ranged from -0.08 to 0.10 (all p = NS). These data suggest that the response to alendronate therapy over this time period cannot be measured by accuDXA or Sunlight SOS at the sites studied.

Tolerability of risedronate in postmenopausal women intolerant of alendronate

Bisphosphonates are effective treatments for osteoporosis, but some have been associated with upper gastrointestinal intolerance. This randomized, double-blind study assessed the upper gastrointestinal tolerability of risedronate in postmenopausal women who had discontinued alendronate treatment because of upper gastrointestinal adverse events. Sixty-six women who had previously discontinued treatment with alendronate 10 mg/day because of upper gastrointestinal symptoms received placebo (N=31) or risedronate 5 mg (N=35) daily for 3 months. The primary outcome was the rate of discontinuation due to upper gastrointestinal adverse events: 5/31 (16.1%) in the placebo group, and 4/35 (11.4%) in the risedronate group. Discontinuation rates were also similar in the two treatment groups among subgroups of patients with a history of gastrointestinal disorder, prior use of acid suppression drugs, and concomitant use of NSAIDs. The overall incidence of upper gastrointestinal events was comparable between the placebo (19.4%) and risedronate (20.0%) groups. Overall, risedronate 5 mg/day for 3 months was as well tolerated as placebo in patients who could not tolerate alendronate 10 mg. These results are consistent with, and complement those from previous studies showing that risedronate 5 mg has a gastrointestinal tolerability similar to that of placebo.

Assessment of bone status using speed of sound at multiple anatomical sites

Studies in vitro and in vivo have shown that quantitative ultrasound (QUS) is a valid tool for the assessment of bone status. Current QUS methods using the transmission technique are limited to one peripheral bone site. A new system, Sunlight Omnisense (Omnisense, Sunlight Medical Ltd., Rehovot, Israel), measures speed of sound (SOS, in m/s) along the surface of the bone based on an axial transmission technique. The Omnisense can measure SOS at several anatomical sites. This study evaluated the SOS at different anatomical sites in a healthy population. A total of 334 adult women from three research centers in the USA and Canada with a mean (+/- SD) age of 48.8 (+/- 17.4) years were enrolled in this study. SOS was measured at the proximal third phalanx, distal one third radius, midshaft tibia, and fifth metatarsal. The mean SOS (+/- SD) values for the phalanx, radius, tibia and metatarsal were 3984 (+/- 221), 4087 (+/- 147), 3893 (+/- 150) and 3690 (+/- 246) m/s, respectively. Each anatomical site SOS was significantly different (p < 0.001) from that of the other sites. SOS at the different anatomical sites was modestly, but significantly, correlated (r = 0.31 to 0.56, p < 0.001). Similar correlation coefficients were obtained for the T scores. The mean T scores for subjects over the age of 60 years were -1.94, -2.01, -0.97 and -1.42 for the phalanx, radius, tibia and metatarsal, respectively. The age of peak SOS and the rate of change thereafter varied with anatomical site, implying that the prevalence of osteopenia and osteoporosis was site-dependent if only one T score cut-off point was used. Comparing individuals, 10% to 17% of patients had T scores that differed by more than a factor of 2 between sites. Weight and age were some of the contributing factors to this heterogeneity. The Omnisense provides an opportunity to assess bone status at different anatomical sites. Whether or not combining measurements from all these anatomical sites will improve osteoporosis management still needs to be determined.

Consensus statement on the modern therapy of Paget's disease of bone from a Western Osteoporosis Alliance symposium. Biannual Foothills Meeting on Osteoporosis, Calgary, Alberta, Canada, September 9-10, 2000

BACKGROUND

Bisphosphonate therapy remains the most effective way of controlling Paget's disease of bone (PD). Along with salmon calcitonin, etidronate has been the mainstay of therapy for approximately 20 years. However, the advent of newer bisphosphonates with different molecular actions on osteoclasts warrants a reevaluation of optimal treatment.

OBJECTIVE

At a symposium of the Western Osteoporosis Alliance, physicians with experience in the management of PD met to review currently available information and generate this consensus statement as a guideline for clinicians and a source of information for health care payers.

METHODS

All available randomized, double-blind, controlled studies that compared the efficacy of newer bisphosphonates with that of etidronate in the treatment of PD were identified through a search of MEDLINE using the terms Paget's disease, bisphosphonates, pamidronate, etidronate, alendronate, risedronate, tiludronate, clodronate, calcitonin, and salmon calcitonin. Because no such studies have been conducted for pamidronate, clodronate, or calcitonin, these drugs were not included in the analysis.

CONCLUSIONS

The consensus of the symposium was that etidronate has little place in the modern management of PD. Newer bisphosphonates such as alendronate and risedronate provide significant therapeutic advantages over etidronate, both in the extent of reduction in bone-specific alkaline phosphatase (BSAP) and/or total serum alkaline phosphatase (SAP) and in the duration of remission, as measured by normalization of BSAP/SAP. In the absence of a direct comparison between alendronate and risedronate in the treatment of PD, physician choice is likely to be based on personal experience, relative cost, and differences in dosing.

Positive effect of etidronate therapy is maintained after drug is terminated in patients using corticosteroids

Following a 52-wk randomized controlled trial of intermittent cyclic etidronate therapy in patients using corticosteroids, we performed a 52-wk open-label trial of calcium alone in 114 corticosteroid-treated patients to determine whether the beneficial effect of etidronate is maintained after the drug is discontinued. All patients were given 500 mg/d of elemental calcium. Sixty-one and 53 patients made up the former placebo and etidronate groups, respectively. A total of 89 (98%) of patients in the former placebo and etidronate groups remained on corticosteroids throughout the second year. The mean (SE) percentage change in bone mineral density of the lumbar spine, femoral neck, and trochanter were compared between groups. The difference between groups in mean percentage change from baseline (wk 0, initiation of etidronate or placebo therapy) in the bone density of the lumbar spine, femoral neck, and trochanter, following 104 wk, was 3.8 (0.9), 3.0 (1.1), and 4.3 (1.1), respectively (p < 0.05, all sites), in favor of the former etidronate group. While not significant, the former placebo group demonstrated a slightly larger rate of decline in bone density over the second year than the former etidronate group at all three sites. Following the discontinuation of etidronate therapy, there was no accelerated bone loss and there was evidence of a residual protective effect in both the lumbar spine and femoral neck for up to 1 yr posttreatment.

Multisite bone ultrasound measurement on North American female reference population

The Sunlight Omnisense is a portable quantitative ultrasound device that measures speed of sound (SOS) at multiple skeletal sites and therefore has the potential to provide a more complete assessment of an individual's overall fracture risk than single-site measurements such as the calcaneus. To provide a robust normative female database, 545 healthy Caucasian women ages 20-90 were recruited at five centers across North America. SOS measurements were obtained from the distal one-third radius, proximal third phalanx, midshaft tibia, and fifth metatarsal. The results demonstrate that peak SOS occurs around the age of 40, with maximum mean values of 4161, 3928, 3786, and 4092 m/s seen at the radius, tibia, metatarsal, and phalanx, respectively. Maximal rate of decline of SOS was seen in the decade following menopause (-12.4, -9.2, -12.1, and -18.8 m/s at the radius, tibia, metatarsal, and phalanx, respectively). Reproducibility between successive measurements indicates high precision, with standardized coefficients of variance ranging between 1.5 and 4.5%. Greatest precision was seen at the metatarsal. Further work is required to clarify the biologic significance of multisite SOS measurements and their use in the assessment of fracture risk.

Enhancement of bone mass in osteoporotic women with parathyroid hormone followed by alendronate

Treatment of osteoporosis with PTH causes a marked increase in vertebral bone mineral density (BMD). However, this effect is rapidly reversed when the treatment is stopped. The purpose of the present study was to determine whether the bisphosphonate alendronate could preserve or enhance bone density in patients previously treated with PTH. Sixty-six postmenopausal osteoporotic women were treated for 1 yr with 50, 75, or 100 microg recombinant human PTH-(1-84) or placebo, and then were given 10 mg alendronate daily for an additional year. BMD was measured in the femoral neck, lumbar spine, and whole body. Markers of bone turnover included skeletal alkaline phosphatase, osteocalcin, and N-telopeptide. During the first year, changes in BMD (mean +/- SD) in women receiving PTH (all doses combined) were 7.1 +/- 5.6% (spine), 0.3 +/- 6.2% (femoral neck), and -2.3 +/- 3.3% (total body). After switching to alendronate for 1 yr in women who previously had received PTH, mean changes in BMD were 13.4 +/- 6.4% (spine), 4.4 +/- 7.2% (femoral neck), and 2.6 +/- 3.1% (whole body). In the subgroup of patients who had received the highest dose of PTH, the mean increase in vertebral BMD was 14.6 +/- 7.9%. All markers of bone turnover increased during treatment with PTH and decreased to below baseline after 1 yr of alendronate. In conclusion, sequential treatment of osteoporosis with PTH and alendronate results in an increase in vertebral bone density that is considerably more than has been reported with alendronate or estrogens alone. This combination of drugs may be a useful approach to maximizing bone density in women with vertebral osteoporosis.

Management of corticosteroid-induced osteoporosis

OBJECTIVES

To educate scientists and health care providers about the effects of corticosteroids on bone, and advise clinicians of the appropriate treatments for patients receiving corticosteroids.

METHODS

This review summarizes the pathophysiology of corticosteroid-induced osteoporosis, describes the assessment methods used to evaluate this condition, examines the results of clinical trials of drugs, and explores a practical approach to the management of corticosteroid-induced osteoporosis based on data collected from published articles.

RESULTS

Despite our lack of understanding about the biological mechanisms leading to corticosteroid-induced bone loss, effective therapy has been developed. Bisphosphonate therapy is beneficial in both the prevention and treatment of corticosteroid-induced osteoporosis. The data for the bisphosphonates are more compelling than for any other agent. For patients who have been treated but continue to lose bone, hormone replacement therapy, calcitonin, fluoride, or anabolic hormones should be considered. Calcium should be used only as an adjunctive therapy in the treatment or prevention of corticosteroid-induced bone loss and should be administered in combination with other agents.

CONCLUSIONS

Bisphosphonates have shown significant treatment benefit and are the agents of choice for both the treatment and prevention of corticosteroid-induced osteoporosis.

Intermittent etidronate therapy to prevent corticosteroid-induced osteoporosis

BACKGROUND AND METHODS

Osteoporosis is a recognized complication of corticosteroid therapy. Whether it can be prevented is not known. We conducted a 12-month, randomized, placebo-controlled study of intermittent etidronate (400 mg per day for 14 days) followed by calcium (500 mg per day for 76 days), given for four cycles, in 141 men and women (age, 19 to 87 years) who had recently begun high-dose corticosteroid therapy. The primary outcome measure was the difference in the change in the bone density of the lumbar spine between the groups from base line to week 52. Secondary measures included changes in the bone density of the femoral neck, trochanter, and radius and the rate of new vertebral fractures.

RESULTS

The mean (+/-SE) bone density of the lumbar spine and trochanter in the etidronate group increased 0.61 +/- 0.54 and 1.46 +/- 0.67 percent, respectively, as compared with decreases of 3.23 +/- 0.60 and 2.74 +/- 0.66 percent, respectively, in the placebo group. The mean differences between the groups after one year were 3.72 +/- 0.88 percentage points for the lumbar spine (P = 0.02) and 4.14 +/- 0.94 percentage points for the trochanter (P = 0.02). The changes in the femoral neck and the radius were not significantly different between the groups. There was an 85 percent reduction in the proportion of postmenopausal woman with new vertebral fractures in the etidronate group as compared with the placebo group (1 of 31 patients vs. 7 of 32 patients, P = 0.05), and the etidronate-treated postmenopausal women also had significantly fewer vertebral fractures per patient (P = 0.04).

CONCLUSIONS

Intermittent etidronate therapy prevents the loss of vertebral and trochanteric bone in corticosteroid-treated patients.

Serum insulin, IGF-I,IGF-II and growth hormone, and left ventricular mass in noninsulin-dependent mellitus

OBJECTIVE

To investigate whether serum insulin, insulin-like-growth factor I (IGF-I),insulin-like-growth factor II (IGF-II) and growth hormone (GH)--each of which is a known trophic factor in vitro for the cardiomyocyte, and levels of which can be altered in noninsulin-dependent diabetes mellitus (NIDDM)--related of left ventricular (LV) mass in patients with NIDDM.

DESIGN

Observational study.

SETTING

University teaching hospital.

PATIENTS AND METHODS

Patients with NIDDM without signs, symptoms or past history of hypertension, ischemic or valvular heart disease, or heart failure were recruited from the diabetes clinic of an university hospital. Fasting patients had blood drawn for determination of serum insulin, IGF-I, IGF-II and GH by radioimmunoassay. Height, weight, and blood pressure were recorded. An electrocardiogram was obtained and echocardiography were performed for calculation of LV mass.

RESULTS

Patients' average age was 54.7 +/-1.6 years, and duration of NIDDM was 9.3 +/- 1.2 years. LV mass was 113.7 +/- 8.9 g/m2 in men (n=13) and 104.1 +/- 10.8 g/m2 in women (n=10). Serum insulin was 25.3 +/- ng/mL, IGF-I was 255 +/- 15 ng/mL, IGF-II was 0.62 +/- 0.05 microg/mL and GH was 5.4 +/- 0.5 ng/mL. There were no significant differences in LV mass among patients with serum insulin, IGF-I, IGF-II or GH in the upper compared with the lower 50th percentile. There were no significant differences in serum insulin, IGF-I, IGF-II or GH among patients in the upper compared with the lower 50th percentile for LV mass. Standardization of LV mass for body size, either by height or body surface area, did not alter the relationships. The correlation coefficients from linear least squares regression analysis between these hormones and LV mass were low (r<0.003), suggesting that even much larger sample sizes might not alter these findings.

CONCLUSIONS

These data suggest that circulating total serum concentrations of growth factor (insulin, IGF-I, IGF-II and GH) are not determinants of LV mass in nonhypertensive patients with NIDDM.

Radiotherapy in the management of thyroid orbitopathy. Computed tomography and clinical outcomes

OBJECTIVE

We investigated the long-term outcome of patients with thyroid orbitopathy treated with orbital radiotherapy using quantitative clinical measurements and orbital computed tomographic morphometric changes.

DESIGN

Patients who had undergone orbital radiotherapy for thyroid orbitopathy at least 1 year previously were retrospectively recalled for follow-up examination and computed tomography. Controls were patients with similar disease activity but who had not undergone radiotherapy.

SETTING

Subspecialty clinic in a university teaching hospital.

PATIENTS

Twenty-one patients (42 orbits) who underwent radiotherapy and six clinically comparable patients who had not undergone radiotherapy (12 orbits).

INTERVENTION

Standardized, super-voltage, orbital radiotherapy.

MEASUREMENTS

Five clinical indexes of orbitopathy and six computed tomographic indexes were examined for interval changes.

RESULTS

The orbital computed tomographic muscle-diameter index enlargement ratio did not change in either group (radiotherapy group, 1.54 to 1.51, not significant; nonradiotherapy group, 1.37 to 1.36, not significant). The mean (+/- SEM) number of muscles with low-density areas increased in both groups (radiotherapy group, 1.1 [+/- 1.9] muscles per orbit; P < .001). Soft-tissue signs improved significantly with lesser improvements in extraocular muscle function in both groups. Proptosis, visual acuity, and intraocular pressure rise on upgaze did not improve significantly in either group.

CONCLUSIONS

No changes in muscle size measured with computed tomography were found in either patients undergoing radiotherapy or patients not undergoing radiotherapy after long-term follow-up. Clinical indexes of thyroid orbitopathy, especially soft-tissue signs, improved on follow-up, but this was not influenced by the method of treatment.

Expression of human thyroid peroxidase in insect cells using recombinant baculovirus

The baculovirus expression system was used to overexpress recombinant human thyroid peroxidase. Sf-9 cells infected with the recombinant virus AcMNPV-hTPO synthesized hTPO protein (hTPO-bac) immunogenic on Western blots when probed with either rabbit anti-TPO peptide sera or pooled human anti-TPO sera (MS12/89). hTPO-bac was a major constituent of the membrane fraction from the infected cells, constituting 14.9% and 10.1% of the 1% deoxycholate-soluble and insoluble fractions, respectively, as judged by densitometry. Recombinant hTPO-bac was extracted from cellular membranes with 1% deoxycholate and partially purified by Sepharose 6B column chromatography. Specific immunoreactivity of MS12/89 to hTPO-bac on microtiter plates was seen using ELISA. Detergent extract from wild-type virus-infected Sf-9 cells was used as background control antigen; no specific reactivity to either hTPO-bac or control antigen was seen with control sera. To determine antigenic potency, MS12/89 was incubated with increasing concentrations of various preparations of hTPO antigen and with ovalbumin as control. The capacity of the partially purified hTPO-bac to immunoneutralize human anti-hTPO standard at 50% inhibition of binding was 0.01 U/microgram hTPO-bac (NIBSC Units), compared with 0.5 U/microgram and 0.06 U/microgram for natural hTPO and CHO-hTPO, respectively. When ELISA was performed using clinical samples of human sera to detect hTPO autoantibodies, results using hTPO-bac correlated well with those using hTPO from Graves' thyroid tissue (r = 0.85, p = 0.02) and those using recombinant hTPO from Chinese hamster ovary cells (hTPO-CHO) (r = 0.85, p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Endogenous antigen presentation by autoantigen-transfected Epstein-Barr virus-lymphoblastoid cells. I. Generation of human thyroid peroxidase-reactive T cells and their T cell receptor repertoire

To develop a model for endogenous thyroid autoantigen presentation, we transfected EBV-transformed B lymphoblastoid cell lines (EBV-LCL), established from patients with autoimmune thyroid disease and normal controls, with cDNA for the human thyroid autoantigen thyroid peroxidase (hTPO). hTPO-antigen presentation to patient peripheral blood T cells was demonstrated after stimulation in vitro for 7 d with irradiated hTPO-transfected or untransfected autologous EBV-LCL. Anti-hTPO-reactive T cells were subsequently cloned in the presence of irradiated, autologous hTPO-transfected EBV-LCL and IL-2.10 T cell-cloned lines exhibited specific hTPO-induced proliferation (stimulation indices of 2.1-7.9) towards autologous hTPO-transfected EBV-LCL, and were subjected to human T cell receptor (hTCR) V gene analysis, using the PCR for the detection of V alpha and V beta hTcR gene families. The results indicated a preferential use of hTCR V alpha 1 and/or V alpha 3 in 9 of the 10 lines. In contrast, hTCR V beta gene family use was more variable. These data demonstrate a model for the endogenous presentation of human thyroid peroxidase in the absence of other thyroid specific antigens. The high frequency of antigen-specific T cells obtained from PBMC using this technique will facilitate further studies at both the functional and hTCR V gene level.

The initial clinical characteristics of Graves' orbitopathy vary with age and sex

A better understanding of the clinical nature of Graves' orbitopathy will aid in the treatment of the disease as well as help to form a basis for clinical and pathophysiologic investigations. We studied the clinical data of 557 consecutive patients who were referred for treatment of Graves' orbitopathy. Clinical indexes were calculated based on ophthalmologic variables measured, grouped in the following categories: soft tissue, proptosis, muscle limitation, increase in intraocular pressure on upgaze, corneal staining, and visual acuity. The mean age at onset of orbital disease was 43.9 years for men and 44.4 years for women, an average of 2.5 years from the onset of thyroid disease. The male-female ratio was 0.29 in all age groups. Women were more likely to present with orbitopathy and hypothyroidism than were men (20% vs 11%) and less likely to be euthyroid (16% vs 34%, P < .01). Patients older than 50 years, compared with their younger counterparts, more often had symptoms of impaired ocular motility (32% vs 12%), signs of soft-tissue involvement (77.5% vs 68.6%), asymmetric soft-tissue involvement (15.6% vs 7.8%), more limited upward duction (22.2 degrees vs 29.4 degrees), and more impaired LogMAR visual acuity (0.092 vs 0.047, P < .01). Men had more limited upward duction than women (24.6 degrees vs 27.1 degrees) and greater increases in intraocular pressure on upgaze (7.80 mm Hg vs 5.78 mm Hg, P < .001). These data show thyroid orbitopathy to be a disease most common in younger women, but more severe, by most indexes, in men and patients older than 50 years. These groups of patients are also more likely to have asymmetric or euthyroid disease.

A 64 kDa membrane antigen is a recurrent epitope for natural autoantibodies in patients with Graves' thyroid and ophthalmic diseases

OBJECTIVE

We have explored the recently described 64 kDa extraocular muscle antigen that is associated with autoantibodies in the serum of patients with severe Grave's ophthalmopathy. The localization of the antigen and the specificity of autoantibodies for both eye muscle antigens and ophthalmopathy patients were investigated.

DESIGN

Western blotting and immunoprecipitation of metabolically labelled antigen from eye muscle and control tissues with sera from ophthalmopathy, Graves' without ophthalmopathy, and normals were used.

PATIENTS

Sera from normals (n = 9), patients with recent onset Graves' ophthalmopathy (n = 23), and patients with Graves' disease without ophthalmopathy (n = 8) were utilized.

MEASUREMENTS

Immunoblots using detergent phase separated (amphiphilic) antigen preparations from fetal eye muscle, skeletal muscle and control tissues were quantitated. Metabolically labelled eye muscle and skeletal muscle antigens were immunoprecipitated using patient and control IgG.

RESULTS

In the eye muscle detergent phase, immunoreactivity around 64 kDa was detected in 30% of the patients with ophthalmopathy (n = 23) as well as 38% of patients with Graves' disease and no ophthalmopathy (n = 8) and in 30% of normal sera (n = 9). There was significantly more of this anti-64 kDa reactivity in sera from the ophthalmopathy patients compared with the normals (P less than 0.01). 64 kDa reactivity to detergent phase antigens prepared from human thyroid, skeletal muscle, brain, and liver was also observed with these positive sera indicating the polyreactivity of the IgG interactions to conserved antigens in this region.

CONCLUSIONS

We conclude that IgG antibodies binding to a recurrent 64 kDa antigen are present in many normal human sera, with increased concentrations detectable in sera from Graves' ophthalmopathy patients. Such 'specificity-crossover' with similar molecular weight transmembrane antigens is likely to be caused by natural autoantibodies reacting with recurrent autoepitopes rather than a factor aetiological in the disease process.

Detection of autoantibodies to recombinant human thyroid peroxidase by sensitive enzyme immunoassay

Autoantibodies to thyroid peroxidase (TPO), the thyroid 'microsomal' antigen, are widely utilized in the diagnosis of human autoimmune thyroid disease. Crude human thyroid preparations of TPO are of differing potency, contain residual thyroglobulin (Tg) and other human membrane antigens, and are available in only limited amounts. Hence, immunoassays for anti-TPO are unstandardized and of variable sensitivity and specificity. We co-transfected the Chinese hamster ovary (CHO) cell line with a full-length human TPO cDNA expression plasmid. We selected a high expressing recombinant TPO positive cell population (CHO-TPO) by Northern blot analysis, then fluorescence laser flow cytometry using both human polyclonal and murine monoclonal anti-TPO antibodies. Solubilized 100,000 g membrane preparations from both CHO-TPO and CHO cells were used as antigens in a specific ELISA with CHO antigen serving as background control. In a selected series of known anti-TPO positive (n = 46) and negative (n = 73) sera there was a high correlation between ELISAs utilizing recombinant or natural-TPO antigen (r = 0.93). There appeared to be no difference in the affinity of high titre human anti-TPO for recombinant and natural-TPO antigen with both ELISAs able to detect 0.05 U/ml of anti-TPO activity (reference preparation NIBSC 66/387). These data predict a new era in standardized thyroid autoantibody testing utilizing recombinant antigen preparations.