Cost effectiveness of screening perimenopausal white women for osteoporosis: bone densitometry and hormone replacement therapy

Cost-Effectiveness of Osteoporosis Screening and Treatment with Hormone Replacement Therapy, Raloxifene, or Alendronate

Recent information about osteoporosis treatments and their nonfracture side effects suggests the need for a new costeffectiveness analysis. The authors estimate the cost effectiveness of screening women for osteoporosis at age 65 and treating those who screen positive with hormone replacement therapy (HRT), raloxifene, or alendronate. A Markov model of osteoporosis disease progression simulates costs and outcomes of women aged 65 years. Incremental cost effectiveness ratios of screen-and-treat strategies are calculated relative to a no-screen, no-treat (NST) strategy. Disease progression parameters are derived from clinical trials; cost and quality-of-life parameters are based on review of cost databases and cost-effectiveness studies. Women are screened using dual-energy x-ray absorptiometry, and women screening positive are treated with HRT, raloxifene, or alendronate. Screening and treatment with HRT increase costs and lower quality-adjusted life years (QALYs; relative to the NST strategy). The only scenario (of several) in the sensitivity analysis in which HRT increases QALYs is when it is assumed that there are no drug-related (nonfracture) health effects. Raloxifene increases costs and QALYs; its cost-effectiveness ratio is $447,559 per QALY. When prescribed for the shortest duration modeled, raloxifene’s cost-effectiveness ratio approached $133,000 per QALY. Alendronate is the most cost-effective strategy; its cost-effectiveness ratio is $72,877 per QALY. Alendronate’s cost-effectiveness ratio approaches $55,000 per QALY when treatment effects last for 5 years or the discount rate is set to zero. The authors conclude that screening and treating with alendronate are more costeffective than screening and treating with raloxifene or HRT. Relative to an NST strategy, alendronate has a fairly good cost-effectiveness ratio

A systematic review of models used in cost-effectiveness analyses of preventing osteoporotic fractures

This review was aimed at the evolution of health economic models used in evaluations of clinical approaches aimed at preventing osteoporotic fractures. Models have improved, with medical continuance becoming increasingly recognized as a contributor to health and economic outcomes, as well as advancements in epidemiological data. Model-based health economic evaluation studies are increasingly used to investigate the cost-effectiveness of osteoporotic fracture preventions and treatments. The objective of this study was to carry out a systematic review of the evolution of health economic models used in the evaluation of osteoporotic fracture preventions. Electronic searches within MEDLINE and EMBASE were carried out using a predefined search strategy. Inclusion and exclusion criteria were used to select relevant studies. References listed of included studies were searched to identify any potential study that was not captured in our electronic search. Data on country, interventions, type of fracture prevention, evaluation perspective, type of model, time horizon, fracture sites, expressed costs, types of costs included, and effectiveness measurement were extracted. Seventy-four models were described in 104 publications, of which 69% were European. Earlier models focused mainly on hip, vertebral, and wrist fracture, but later models included multiple fracture sites (humerus, pelvis, tibia, and other fractures). Modeling techniques have evolved from simple decision trees, through deterministic Markov processes to individual patient simulation models accounting for uncertainty in multiple parameters. Treatment continuance has been increasingly taken into account in the models in the last decade. Models have evolved in their complexity and emphasis, with medical continuance becoming increasingly recognized as a contributor to health and economic outcomes. This evolution may be driven in part by the desire to capture all the important differentiating characteristics of medications under scrutiny, as well as the advancement in epidemiological data relevant to osteoporosis fractures.

Clinical and economic characteristics of hip fracture patients with and without muscle atrophy/weakness in the United States

This retrospective analysis of hip fracture patients with and without muscle atrophy/weakness (MAW) revealed that those with MAW had significantly higher healthcare utilization and costs compared with hip fracture patients without MAW.

PURPOSE

Examine the demographics, clinical characteristics, and healthcare resource utilization and costs of hip fracture patients with and without MAW.

METHODS

Using a large US claims database, individuals who were newly hospitalized for hip fracture between 1 Jan 2006 and 30 September 2009 were identified. Patients aged 50-64 years with commercial insurance (Commercial) or 65+ years with Medicare supplemental insurance (Medicare) were included. The first hospitalization for hip fracture was defined as the index stay. Patients were categorized into three cohorts: patients with medical claims associated with MAW over the 12 months before the index stay (pre-MAW), patients whose first MAW claim occurred during or over the 12 months after the index stay (post-MAW), and patients without any MAW claim (no-MAW). Multivariate regressions were performed to assess the association between MAW and healthcare costs over the 12-month post-index period, as well as the probability of re-hospitalization.

RESULTS

There were 26,122 Medicare (pre-MAW, 839; post-MAW, 2,761; no-MAW, 22,522) and 5,100 Commercial (pre-MAW, 132; post-MAW, 394; no-MAW, 4,574) hip fracture patients included in this study. Controlling for cross-cohort differences, both the pre-MAW and post-MAW cohorts had significantly higher total healthcare costs (Medicare, $7,308 and $18,753 higher; Commercial, $18,679 and $25,495 higher) than the no-MAW cohort (all p < 0.05) over the 12-month post-index period. The post-MAW cohort in both populations was also more likely to have any all-cause or fracture-related re-hospitalization during the 12-month post-index period.

CONCLUSIONS

Among US patients with hip fractures, those with MAW had higher healthcare utilization and costs than patients without MAW.

Modeling asthma exacerbations through lung function in children

BACKGROUND

Formal economic evaluation using a model-based approach is playing an increasingly important role in health care decision making.

OBJECTIVE

To develop a model by using an objective measure of lung function-- prebronchodilator FEV(1) as a percent of predicted (FEV(1)% predicted)--as the primary independent factor to predict the frequency of adverse events related to the exacerbation of asthma on a population level.

METHODS

We developed a Markov simulation model of childhood asthma by using data from the Childhood Asthma Management Program. The primary outcomes were the result of asthma exacerbations defined as hospitalizations, emergency department (ED) visits, and the need for oral corticosteroid therapy. Predicted monthly frequencies for each acute event were based on negative binomial regression equations estimated from the placebo arm of the Childhood Asthma Management Program with covariates of age, prebronchodilator FEV(1)% predicted, time in study, prior hospitalizations, and prior nocturnal awakenings.

RESULTS

Simulated versus observed mean number of acute events were similar within the placebo and treatment groups. While the trial demonstrated treatment effects of 48% reduction in hospitalizations, 46% reduction in ED visits, and 44% reduction in the need for oral corticosteroid therapy at 48 months, the model simulated similar reductions of 49% in hospitalizations, 41% in ED visits, and 46% in the need for oral corticosteroid therapy.

CONCLUSIONS

Our findings suggest that longitudinal intervention effects may be modeled through FEV(1)% predicted to estimate hospitalizations, ED visits, and need for oral corticosteroid therapy in childhood asthma for planning and evaluation purposes.

Cost Effectiveness of Fracture Prevention in Postmenopausal Women Who Receive Aromatase Inhibitors for Early Breast Cancer

Purpose

Aromatase inhibitors (AIs) increase the risk of osteoporosis and related fractures in postmenopausal women who receive adjuvant AIs for hormone receptor (HR) –positive early breast cancer (EBC). We compared the cost effectiveness of alternative screening and treatment strategies for fracture prevention.

Methods

We developed a Markov state transition model to simulate clinical practice and outcomes in a hypothetical cohort of women age 60 years with HR-positive EBC starting a 5-year course of AI therapy after primary surgery for breast cancer. Outcomes were quality-adjusted life-years (QALYs), lifetime cost, and incremental cost-effectiveness ratio (ICER). We compared the following strategies: no intervention; one-time bone mineral density (BMD) screening and selective bisphosphonate therapy in women with osteoporosis or osteopenia; annual BMD screening and selective bisphosphonate therapy in women with osteoporosis or osteopenia; and universal bisphosphonate therapy.

Results

ICERs for annual BMD screening followed by oral bisphosphonates for those with osteoporosis, annual BMD screening followed by oral bisphosphonates for those with osteopenia, and universal treatment with oral bisphosphonates were $87,300, $129,300, and $283,600 per QALY gained, respectively. One-time BMD screening followed by oral bisphosphonates for those with osteoporosis or osteopenia was dominated. Our results were sensitive to age at the initiation of AI therapy, type of bisphosphonates, post-treatment residual effect of bisphosphonates, and a potential adjuvant benefit of intravenous bisphosphonates.

Conclusion

In postmenopausal women receiving adjuvant AIs for HR-positive EBC, a policy of baseline and annual BMD screening followed by selective treatment with oral bisphosphonates for those diagnosed with osteoporosis is a cost-effective use of societal resources.

Cost-effectiveness of fracture prevention in men who receive androgen deprivation therapy for localized prostate cancer

BACKGROUND

Androgen deprivation therapy (ADT) increases the risk for fractures in patients with prostate cancer.

OBJECTIVE

To assess the cost-effectiveness of measuring bone mineral density (BMD) before initiating ADT followed by alendronate therapy in men with localized prostate cancer.

DESIGN

Markov state-transition model simulating the progression of prostate cancer and the incidence of hip fracture.

DATA SOURCES

Published literature.

TARGET POPULATION

A hypothetical cohort of men aged 70 years with locally advanced or high-risk localized prostate cancer starting a 2-year course of ADT after radiation therapy.

TIME HORIZON

Lifetime.

PERSPECTIVE

Societal.

INTERVENTION

No BMD test or alendronate therapy, a BMD test followed by selective alendronate therapy for patients with osteoporosis, or universal alendronate therapy without a BMD test.

OUTCOME MEASURES

Incremental cost-effectiveness ratio (ICER), measured by cost per quality-adjusted life-year (QALY) gained.

RESULTS OF BASE-CASE ANALYSIS

The ICERs for the strategy of a BMD test and selective alendronate therapy for patients with osteoporosis and universal alendronate therapy without a BMD test were $66,800 per QALY gained and $178,700 per QALY gained, respectively.

RESULTS OF SENSITIVITY ANALYSES

The ICER for universal alendronate therapy without a BMD test decreased to $100,000 per QALY gained, assuming older age, a history of fractures, lower mean BMD before ADT, or a lower cost of alendronate.

LIMITATIONS

No evidence shows that alendronate reduces actual fracture rates in patients with prostate cancer who receive ADT. The model predicted fracture rates by using data on the surrogate BMD end point.

CONCLUSION

In patients starting adjuvant ADT for locally advanced or high-risk localized prostate cancer, a BMD test followed by selective alendronate for those with osteoporosis is a cost-effective use of resources. Routine use of alendronate without a BMD test is justifiable in patients at higher risk for hip fractures.

Costs and consequences of hip fracture occurrence in old age: An economic perspective

PURPOSE

To summarize the reported short- and long-term costs associated with hip fracture occurrence in old age, based on a systematic literature review of published studies. A further aim is to provide a clinician-oriented discussion of the different types of economic evaluations, with an emphasis on studies that examined potential determinants of the costs of care after hip fracture.

METHOD

Literature review.

MAIN RESULTS

Even after the initial hospitalization, hip fractures continue to generate significant costs throughout the one-year period after discharge, but particularly during the first three months. Cost estimates based on data obtained prospectively from hip-fracture patients and matched controls showed that the costs associated with the treatment of hip-fracture patients are about three times greater than those resulting from the treatment of age and residence-matched controls without a fracture. Two-fifths of these excess costs are incurred during the first three months following hospital discharge. Increasing age at the time of injury and living in an institution before the fracture are among the most important determinants of an increased cost of care after hospital discharge. Programs that focus on continuity of care, adopt a multidisciplinary approach, and accelerate rehabilitation have shown to be able to reduce the cost of care after hip fracture.

CONCLUSIONS

This review emphasizes the importance of current and future interventions to decrease the incidence of hip fracture. While the current review cannot provide definite answers to the questions of cost containment, our review provides critically important evidence about the need to base health policy decisions on empirical observations. Comprehensive economic analyses of financial costs and health outcomes are needed to develop cost-effective strategies.

Cost-effectiveness of the treatment and prevention of osteoporosis--a review of the literature and a reference model

OBJECTIVE

The purpose of the paper is to update and review the latest developments related to modelling and economic evaluation of osteoporosis in the period 2002-2005 and further to present a reference model for the assessment of the cost-effectiveness of the prevention and treatment of osteoporosis.

DISCUSSION

The reference model is intended to be used for fracture specific interventions affecting the risk of fracture. An interface version and an extensive description of the model is available on the internet ( http://www.healtheconomics.se ) and also accessible via the International Osteoporosis Foundation ( http://www.osteofound.org ). The purpose of the reference model is to improve the quality and comparability of cost-effectiveness analysis in the osteoporosis field and to serve as a tool for validation of present and future cost-effectiveness models. The reference model allows the cost-effectiveness analysis to be carried out from a societal perspective including intervention, morbidity and mortality costs. The model has been extensively tested and calibrated, and meets the properties of good decision analytic modelling. The model is a state transition Markov cohort model, which is characterised by a 50-year time horizon divided into one year cycle lengths. The following health states are included: "healthy", "hip fracture", "spine fracture", "wrist fracture", "other fracture", and "dead".

CONCLUSION

The model is flexible and allows for the estimation of the cost-effectiveness over different ranges for a selected number of variables (e.g., age, fracture risk, cost of intervention).

Cost-Effectiveness Analysis of Various Screening Methods for Osteoporosis in Perimenopausal Thai Women

OBJECTIVE

To perform a health economics analysis of 5 screening programs for osteoporosis in perimenopausal Thai women comparing two alternatives; without intervention and universal treatment without screening.

DESIGN

A decision analysis was performed to evaluate five screening strategies: Dual energy X-ray absorptiometry (DXA), Quantitative ultrasound sonography (QUS), risk index (clinical risk factors), two-step screening with QUS followed by DXA, and screening with risk index followed by DXA, comparing outcomes without intervention and universal treatment without screening.

RESULTS

The costs for universal treatment, screening by DXA with treatment, screening by QUS with treatment, screening by Risk index with treatment, screening by QUS and DXA with treatment, and screening by Risk index and DXA with treatment strategies to prevent one fracture were 207.82, 88.42, 147.05, 127.67, 71.33, and 60.30 USD, respectively. The cost for no intervention to prevent one fracture is 8.49 USD (1 USD = 40 Thai baht).

CONCLUSION

At present, no intervention is the most cost effective strategy. However, screening with risk index and DXA with treatment became the most cost effective when the patients reached the postmenopausal period and had a high risk index, for which the prevalence of osteoporosis will increase. Cost effective screening guidelines still cannot be explicitly established until further data addressing the association between bone mass measurements in the hip and hip fracture risk, are available.

Economic evaluations of interventions for the prevention and treatment of osteoporosis: a structured review of the literature

Economic evaluations are increasingly being used by decision-makers to estimate the cost-effectiveness of interventions. The objective of this study was to conduct a structured review of economic evaluations of interventions to prevent and treat osteoporosis. Articles were identified independently by two reviewers through searches on MEDLINE, the bibliographies of reviews and identified economic models, and expert opinion, using predefined inclusion and exclusion criteria. Data on country, type and level of interventions, type of fractures, interventions, study population and the authors' stated conclusions were extracted. Forty-two relevant studies were identified. The majority of studies (71%) were conducted in Sweden, the UK and the US. The main interventions investigated were hormone replacement therapy (27%), bisphosphonates (17%) and combinations of vitamin D and calcium (16%). In 38% of studies, hip fracture was the sole fracture outcome. Eighty-eight percent (88%) of studies investigated female populations only. A relatively large number of economic evaluations were identified in the field of osteoporosis. Major changes have recently occurred in the treatment of this disease, following the publication of the results of the Women's Health Initiative trial. Methodological developments in economic evaluations, such as the use of probabilistic sensitivity analysis and cost-effectiveness acceptability curves, have also taken place. Such changes are reflected in the studies that were reviewed. The development of economic models should be an iterative process that incorporates new information, whether clinical or methodological, as it becomes available.

Assessing generalisability in model-based economic evaluation studies: a structured review in osteoporosis

To support decision making, many countries have now introduced some formal assessment process to evaluate whether health technologies represent good 'value for money'. These often take the form of decision models that can be used to explore elements of importance to generalisability of study results across clinical settings and jurisdictions. The objective of this review was to assess whether articles reporting decision-analytic models in the area of osteoporosis provided enough information to enable decision makers in different countries/jurisdictions to fully appreciate the variability of results according to location and be able to apply the evaluation to their own setting. Of the 18 articles included in the review, only three explicitly stated the decision-making audience. It was not possible to infer a decision-making audience in eight studies. The target population was well reported, as were resource and cost data, and clinical data used for estimates of relative risk reduction. However, baseline risk was rarely adapted to the relevant jurisdiction, and when no decision maker was explicit it was difficult to assess whether the reported cost and resource use data were in fact relevant. A few studies used sensitivity analysis to explore elements of generalisability, such as compliance rates and baseline fracture risk rates, although such analyses were generally restricted to evaluating parameter uncertainty. This review found that variability in cost effectiveness across locations is addressed to a varying extent in modelling studies in the field of osteoporosis, limiting their use for decision makers across different locations. Transparency of reporting is expected to increase as methodology develops and decision makers publish 'reference case' type guidance.

Reassessment of the cost-effectiveness of hormone replacement therapy in Sweden: Results based on the Women's Health Initiative randomized controlled trial

Objectives:The purpose of the study is to reassess the cost-effectiveness of hormone replacement therapy (HRT) based on new medical evidence found in the Women's Health Initiative (WHI). Within a model framework using an individual state transition model, the cost-effectiveness of 50- to 60-year-old women with menopausal symptoms is assessed based on a societal perspective in Sweden.

Methods:The model has a 50-year time horizon divided into a cycle length of 1 year. The model consists of the following disease states: coronary heart disease, stroke, venous thromboembolic events, breast cancer, colorectal cancer, hip fracture, vertebral fracture, and wrist fracture. An intervention is modeled by its impact on the disease risks during and after the cessation of therapy. The model calculates costs and quality-adjusted life years (QALYs) with and without intervention. The resulting cost per QALY gained is compared with the value of a QALY gained, which is set to SEK 600,000. The model requires data on clinical effects, risks, mortality rates, quality of life weights, and costs valid for Sweden.

Results:The cost-effectiveness ratios are estimated at approximately SEK 10,000, which is below the threshold value of cost-effectiveness. On the condition that HRT increases the quality of life weight more than 0.013 units, the therapy is cost-effective.

Conclusions:In conclusion, given the new evidence in WHI, there is still a high probability that HRT is a cost-effective strategy for women with menopausal symptoms.

The need for microsimulation to evaluate osteoporosis interventions

Simulations play an increasingly important role in the evaluation of osteoporosis interventions. Existing evaluations have been based on "reduced-form" cohort simulations that do not reflect the complexity and heterogeneity of osteoporosis and its outcomes. Such simplified models offer parsimony and ease of use, but they also are limited in their ability to explain and extrapolate outcomes in a way that is most useful for both clinical and health policy decision makers. Alternatively, evaluations could be based on "structural" microsimulations, which explicitly model the underlying biology of osteoporosis at the individual level. The structural approach presents technical challenges, including the need to obtain more-detailed data and the requirement that underlying biological models be validated. However, evaluations based on structural microsimulation may ultimately provide substantially more useful information, resulting in improved decision making.

Validation of a decision model for preventive pharmacological strategies in postmenopausal women

BACKGROUND

Benefits and risks of a combined hormone replacement therapy (HRT) based on randomized clinical trial emerged on various disease endpoints in 2002. The Women's Health Initiative (WHI) provides an important health answer for healthy postmenopausal women, such as do not use combined HRT to prevent chronic disease, because of the elevated risk of coronary artery disease (CHD), stroke and venous thromboembolism. In March 2004, the NIH stopped the drugs in the estrogen-alone trial after finding an increase risk of stroke and no effect, neither an increase or a decrease, on risk of CHD after an average of 7 years in the trial. On the other hand, raloxifene, which does not seem to significantly increase the risk of cardiovascular events and could retain skeletal benefits without stimulating endometrial and breast tissue, requires decision-makers since no current data on these disease clinical endpoints have been published.

OBJECTIVE

To construct a multi-disease model based on patient-specific risk factor profiles, and to validate the multi-disease model with several tools of internal and external validities.

METHODS

A Markov state model was developed. The risks of these various diseases (including coronary artery disease, stroke, hip fracture and breast cancer) are derived from published hazards proportional models which take into account significant risk factors. Canadian-specific rates and data sources for these transition probabilities are derived from published studies and Canadian Health Statistics. The validation of our model were based on several tools of internal and external validities, such as Canadian life expectancy, population-based incidence rate of diseases, clinical trials and other published life expectancy models.

RESULTS

First, presumably, small changes in the lifetime probability of dying support the hypothesis that the disease states operate in a largely independent fashion. For instance, the difference in the probability of dying from a particular disease by the complete elimination of a selected disease, such as CHD, stroke or breast cancer, ranged from 0.2 to 2.2% of difference in the lifetime probability of dying of these diseases. Second, we demonstrated that the model adequately predicted the Canadian population lifetable and disease-incidence rates from population-based data among women from 45 to 75 years old. The predictions of the model were cross-checked from non-source data, such as predicted outcomes versus observed outcomes from results of clinical trials. Predicted relative risks of CHD event, breast cancer and hip fracture fell in the reported 95% confidence interval of clinical trials. Finally, predicted treatment benefits are comparable with those of published life expectancy models.

CONCLUSIONS

The results of the study demonstrated that this multi-disease model, including coronary artery disease, stroke, hip fracture and breast cancer, is a valid model to predict the impact on life expectancy or number of events prevented for preventive pharmacological interventions.

A cost-effectiveness evaluation of two continuous-combined hormone therapies for the management of moderate-to-severe vasomotor symptoms

OBJECTIVES

After the release of the results of the Women's Health Initiative, an emerging consensus suggests that continuous-combined hormone therapy (CCHT) should be limited to short-term management of moderate-to-severe vasomotor symptoms. This, in turn, raises the important question of the economic value, if any, of short-term CCHT for this indication. We conducted a cost-effectiveness analysis comparing a 1-year treatment course with 1 mg of norethindrone acetate/5 microg of ethinyl estradiol (1/5 NA/EE) or 0.625 mg/day of conjugated estrogens plus 2.5 mg of medroxyprogesterone (0.625/2.5 CEE/MPA) compared with no therapy for the management of moderate-to-severe vasomotor symptoms.

DESIGN

A literature-based Markov model was developed to compare these three options' cost and quality-of-life (QOL) benefits. The impact of therapy on vasomotor symptoms and breakthrough bleeding/spotting on the direct costs of care and QOL were considered.

RESULTS

Compared with no therapy, CCHTs resulted in net increases in quality-adjusted life-years (QALYs) gained (0.110 for 1/5 NA/NE v 0.104 for 0.625/2.5 CEE/MPA). Net costs (v no therapy) were $167 lower for 1/5 NA/NE compared with 0.625/2.5 CEE/MPA. Cost per QALY gained (compared with no therapy) were $6,200 and $8,200, respectively. Cost-effectiveness was most favorable for individuals with more severe symptoms who were less bothered by breakthrough bleeding/spotting.

CONCLUSIONS

A short-term course of CCHT for the sole purpose of managing moderate-to-severe vasomotor symptoms is cost-effective. However, 1/5 NA/NE seemed to be more cost-effective than 0.625/2.5 CEE/MPA. These findings can be used to further refine the role of CCHT and to improve formulary decisions.

Access to bone densitometry increases general practitioners' prescribing for osteoporosis in steroid treated patients

BACKGROUND

Availability of access to bone densitometry in the UK varies widely and there are concerns as to appropriate prescribing. Studies suggest inadequate use of osteoporosis prophylaxis in steroid users, despite recent guidelines.

OBJECTIVE

To examine in a case-control study whether access to bone densitometry affects GPs' osteoporosis prescribing in high risk steroid users.

METHOD

10 general practices were included, five from primary care trusts (PCTs) with access to bone densitometry and five with limited access. Patients receiving prednisolone for >3 months were identified by database search. Patients receiving no prophylaxis other than calcium and vitamin D (Ca/D) were subsequently included. Appropriate patients in five practices were offered DXA scan (cases) and review. Patients in practices without access to scans (controls) were reviewed. GPs' opinions leading to treatment were sought by structured questionnaire.

RESULTS

132 (0.12%) patients were receiving prednisolone for >/=3 months, but no osteoporosis prophylaxis other than Ca/D. Pre-study prophylaxis ranged from 18 to 36%. Of 48 patients scanned, 21 (44%) were abnormal and 18 (38%) received new treatment. 13/44 (30%) controls received new treatment. 10/21 (48%) with abnormal scans started a bisphosphonate, compared with 7/44 (16%) controls (RR = 3, p = 0.004). No difference in risk factors for fracture was found in treated and untreated controls.

CONCLUSIONS

GPs were three times more likely to start potent osteoporosis treatment after abnormal scans than GPs relying on clinical information. In practice, risk factors were not adequately assessed. Database searches may identify patients needing osteoporosis prophylaxis; however, DXA enables more appropriate patient treatment.

Superiority of age and weight as variables in predicting osteoporosis in postmenopausal white women

Identification of women at risk for osteoporosis is of great importance for the prevention of osteoporotic fractures. Routine BMD measurement of all women is not feasible for most populations, hence identification of a high-risk subset of women is an important element of effective preventive strategies.

METHODS

We identified 959 postmenopausal non-Hispanic women aged 51 years and above from the NHANES III study to assess the relative contribution of risk predictors for low BMD at the whole proximal femur and the femoral neck regions. Based on recognized risk factors for osteoporosis identified by a systematic literature search, we ran several multiple linear regression models based on the results of preceding bivariate analyses. We show several models based on their explanatory ability assessed by adjusted r(2), ROC, and C-value analyses rather than on the coefficients and P values. We furthermore examined the sensitivity, specificity, and predictive values of our preferred models for various cutoff T-scores-the choice of which will vary depending on different study goals and population characteristics.

RESULTS

Age and weight were by far the most informative predictors for low bone mineral density out of a list of 20 candidate risk predictors. Our preferred prediction models for the two regions hence contained only two variables: i.e., age and measured weight. The resulting parsimonious model to predict BMD at whole proximal femur had an adjusted r(2) of 0.43, an area under the ROC curve of 0.85, and a C-value of 0.70. Similarly, prediction for BMD at the femoral neck had adjusted r(2), area under the curve, and C-value of 0.39, 0.83, and 0.66, respectively.

CONCLUSIONS

The model equations, predicted T-score = -1.332-0.0404 x (age) + 0.0386 x (measured weight) and predicted T-score = -1.318-0.0360 x (age) + 0.0314 x (measured weight) for whole proximal femur and femoral neck, respectively, can be used in field conditions for screening purposes. More complex prediction equations add little explanatory power. Based on the study goals and the population characteristics, specific cutoff T-scores have to be decided before using these equations.

An economic analysis of hormone replacement therapy for the prevention of fracture in young postmenopausal women

Osteoporosis is a major public health problem that will become increasingly important as our population ages. It leads to fractures that deeply affect the patients' quality of life. Osteoporosis is recognised as a leading factor in healthcare cost worldwide. For years, experts have recommended hormone replacement therapy (HRT), consisting of oestrogen with or without progestin, as the first-line therapy to prevent bone loss in postmenopausal women. Recently published randomised, controlled trials and well-designed meta-analyses confirm that HRT has both advantages and disadvantages. The advantages include prevention of osteoporotic fractures and colorectal cancer. The disadvantages are the resulting adverse effects such as coronary artery disease, stroke, thromboembolic events, breast cancer and cholecystitis. In the light of these findings, medical associations recommend against the routine use of oestrogen and progestin for the prevention of chronic conditions in postmenopausal women. HRT, administered for the prevention of fractures in all young postmenopausal women, would have an additional cost/year of life gained that is too expensive. However, this strategy seems to be cost-effective when young postmenopausal women at high risk for fractures are selected. Even if this strategy seems attractive, the adverse effects of HRT are not acceptable. This situation implies that other treatments must be found to prevent or treat osteoporosis. Among them, calcium and vitamin D were shown to be cost-saving in osteoporosis and even costs-effective in osteopoenia in young postmenopausal women.

Do HEDIS measures reflect cost-effective practices?

PURPOSE

Whether the Health Plan Employer Data and Information Set (HEDIS) performance measures for managed care plans encourage a cost-effective use of society's resources has not been quantified. Our study objectives were to examine the cost-effectiveness evidence for the clinical practices underlying HEDIS 2000 measures and to develop a list of practices not reflected in HEDIS that have evidence of cost effectiveness.

DATA SOURCES

Two databases of economic evaluations (Harvard School of Public Health Cost-Utility Registry and the Health Economics Evaluation Database) and two published lists of cost-effectiveness ratios in health and medicine.

STUDY SELECTION

For each of the 15 "effectiveness of care" measures in HEDIS 2000, we searched the data through 1998 for cost-effectiveness ratios of similar interventions and target populations. We also searched for important interventions with evidence of cost-effectiveness (<$20,000 per life-year [LY] or quality-adjusted life year [QALY] gained), which are not included in HEDIS. All ratios were standardized to 1998 dollars. The data were collected and analyzed during fall 2000 to summer 2001.

DATA EXTRACTION

Cost-effectiveness ratios reporting outcomes in terms of cost/LY or cost/QALY gained were included if they matched the intervention and population covered by the HEDIS measure.

DATA SYNTHESIS

Evidence was available for 11 of the 15 HEDIS measures. Cost-effectiveness ranges from cost saving to $660,000/LY gained. There are numerous non-HEDIS interventions with some evidence of cost effectiveness, particularly interventions to promote healthy behaviors.

CONCLUSIONS

HEDIS measures generally reflect cost-effective practices; however, in a number of cases, practices may not be cost effective for certain subgroups. Data quality and availability as well as study perspective remain key challenges in judging cost effectiveness. Opportunities exist to refine existing measures and to develop additional measures, which may promote a more efficient use of societal resources, although more research is needed on whether these measures would also satisfy other desirable attributes of HEDIS.

The cost-effectiveness of ramipril in the treatment of patients at high risk of cardiovascular events: a Swedish sub-study to the HOPE study

OBJECTIVE

To evaluate if long-term treatment with ramipril is cost-effective in patients at high risk of cardiovascular events.

DESIGN

Randomized double-blind and placebo controlled. Information was gathered prospectively for a number of direct medical, direct nonmedical and indirect costs.

SETTING AND SUBJECT

This is a sub-study to the Heart Outcomes Prevention Evaluation (HOPE) study performed in Swedish patients. All Swedish centres (19; n= 554) were invited to take part and 18 centres agreed to do so (n=537). The patients were managed in a specialist setting with a mean follow-up period of 4.5 years. Main outcome measures. The number of life-years saved was derived from the global HOPE study (n=9297) and subsequently the estimated life expectancy of those who completed the clinical study alive was added to the calculation. Direct medical costs related to cardiovascular disease only were considered in the primary analysis, whilst all kinds of costs and costs for all kinds of diseases were included in subsequent analyses. The cost of added years of life, according to the future cost method, was included in sensitivity analyses.

RESULTS

The cost per life-year gained was SEK 16 600 (Euro 1940) when direct medical costs for cardiovascular reasons only were considered and SEK 45 400 (Euro 5300) when direct medical costs for all diseases were considered. The corresponding costs when direct nonmedical and indirect cost were added to the estimate were SEK 16 100 (Euro 1880) and SEK 54 600 (Euro 6380), respectively. When the future cost method was applied, the cost per life-year gained was SEK 208 300 (Euro 24 300).

CONCLUSION

Ramipril is highly cost-effective in the treatment of patients at high risk of cardiovascular events.

Assessment of osteoporosis using standard radiographs of the wrist

BACKGROUND

This study evaluated the ability of the orthopaedic surgeon to radiographically assess bone density in the wrist with sufficient accuracy to determine which patients require treatment for osteoporosis.

METHODS

Thirty-eight patients with unilateral distal radius fractures, 30 of whom were female, were included in this study. The mean age was 55 years (range 45 to 82). Standard radiographs of the fractured and normal wrists were taken. Dual energy x-ray absorptiometry was performed on the normal distal radius of all patients within 1 week of their injury. The radiographs were viewed in blinded randomized fashion on two separate occasions by three orthopaedic surgeons and once by a fourth. The participants were required to determine the presence of osteoporosis. Visual analog scales (VAS) were used to evaluate (1) porosity, (2) cortical thickness, (3) trabecular thickness, and (4) the number of trabeculae in the ultradistal radius.

RESULTS

Intraobserver agreement assessing osteoporosis averaged 81% (kappa of 0.5393). VAS assessment was unreliable for all four parameters. Radiographic determination of osteoporosis had a specificity of 61% and a sensitivity of 61% using x-rays of the uninjured wrist.

CONCLUSION

We conclude that orthopaedic surgeons cannot predict with sufficient accuracy using plain x-rays whether a patient is significantly osteoporotic.

The impact of risk on preference values: implications for evaluations of postmenopausal osteoporosis therapy

OBJECTIVE

The objective was to assess the impact of different levels of risk of disease on a woman's preferences for health states. Women were provided with health scenarios incorporating different levels of lifetime risks for breast cancer, hip fracture, and coronary heart disease (CHD). In this way, we were able to determine the incremental effect of changes in risks of each disease on preference values.

METHODS AND DATA

Preference values and utility scores were obtained for six health scenarios by both the feeling thermometer (FT) and standard gamble (SG) methods. Scenarios presented the different lifetime risks of CHD, breast cancer, and hip fracture associated with and not associated with long-term use of hormone replacement therapy (HRT) and raloxifene. Risks of breast cancer were based on perceived risks and population risks. The sample population consisted of 40 healthy female volunteers aged between 45 and 65 years randomly selected from the Ottawa-Carleton district.

RESULTS

Based on their perceived risk of breast cancer, the women had higher value scores for the raloxifene risk profile than for both HRT (p = .002) and no therapy (p = .003), with similar results for analyses based on population risks and from utility scores. Regression analysis showed that the risk of breast cancer (p < .001) was the only disease risk that was statistically significantly associated with women's preferences.

CONCLUSIONS

Women had significant preferences over the different risk profiles, primarily due to the incremental effect on changes in values for the risk of breast cancer. Therefore, studies evaluating therapies for osteoporosis should consider patient preferences for living with different risk profiles.

Proton magnetic relaxation in bone marrow related to age and bone mineral density: low-resolution in vitro studies

Detailed analysis of proton spin-spin and spin-lattice relaxation behaviors of the bone marrow in the presence of trabecular bone network was performed at low-resolution (B(0) = 0.496T) on rat vertebrae specimens deprived of spinal cord. Two groups of samples, from young and old healthy animals, were investigated before cellular necrosis had started. BMD measurements were carried out to quantify the expected age-related modifications of the trabecular bone network. 1H-MR measurements were also performed on the same samples, deprived of marrow and saturated with water, in order to control the validity of a possible interpretation of the marrow 1H-MR characteristics, in terms of marrow components, and to investigate the possible employment of these samples to study the trabecular bone network properties. We pointed out that: 1) a bimodal distribution of T(2i) and T(1i) values (distinguishing "fast" and "slow" relaxations) describes satisfactorily all the 1H-MR experimental decays; 2) age-related modifications of the trabecular bone network are marked by correlate variations of the BMD value and of the proton spin-spin relaxation rates in water saturated samples; 3) age-related modifications of marrow are underlined by variations of the average value of the "fast" T(2i) and of the "slow" T(1i) relaxation time distributions, which could be attributed to the marrow components different from the fat granules of the adipose cells. Our results suggest that studies in vitro on bone tissue, by 1H-MR techniques at low-resolution, may contribute to a better bone function characterization and, therefore, to a better clinical utilization of MRI techniques.

Hip fracture prevention: cost-effective strategies

The available literature on cost benefit, cost effectiveness and cost utility of different drug and non-drug regimens in preventing hip fractures was reviewed. The cost of a hip fracture and of the different treatment regimens varied considerably from one country to another. In primary prevention, potential savings only exceeded costs in women over the age of 70 years treated with hormonal replacement therapy (HRT). In the case of HRT, treating those with low bone mineral density levels (secondary prevention) seems to be more cost effective than general treatment (primary prevention). There are few studies that have compared several different preventive regimens. Cost effectiveness is directly related to the cost of the regimen used because there is no significant difference in their effectiveness. That is, a high cost regimen such as bisphosphonates would be less cost effective than a low cost regimen such as HRT, judged from existing literature. High risk groups can be identified (nursing home residents) and treated with low cost interventions (calcium plus vitamin D or hip protectors). Considerable differences in the estimates used for the efficacy of different regimens in studies exist. Further studies comparing several hip fracture preventive regimens are required in order to establish the most cost-effective strategy.

Cost effectiveness of nasal calcitonin in postmenopausal women: use of Cochrane Collaboration methods for meta-analysis within economic evaluation

OBJECTIVE

To assess the cost effectiveness of nasal calcitonin (Miacalcin) compared with no therapy, alendronate or etidronate in the treatment of postmenopausal women with previous osteoporotic fracture.

DESIGN AND SETTING

Meta-analysis followed by economic analysis.

PERSPECTIVE

A Canadian provincial Ministry of Health.

METHODS

The meta-analysis of randomised controlled clinical trials was based on the recommendations of the Cochrane Collaboration. Economic analysis was conducted within a Markov model using probabilities and costs derived from Canadian sources.

RESULTS

The meta-analysis found evidence of the positive effect of both nasal calcitonin and alendronate in reducing the risks of hip, wrist and vertebral fractures in postmenopausal women. However, there was a lack of evidence of the effect of etidronate on hip and wrist fractures. For a 65-year-old woman, with 5 years' therapy, the incremental cost per quality-adjusted life-year (QALY) gained for nasal calcitonin was 46,500 Canadian dollars ($Can) compared with no therapy and $Can32,600 compared with etidronate (1998 values). Comparison with alendronate was highly sensitive to the inclusion of one specific trial.

CONCLUSIONS

Given the results of the analysis, based on current evidence, nasal calcitonin can be considered at the margins of being cost effective when compared with no therapy. Compared with active therapy, nasal calcitonin can be considered more cost effective than etidronate, but its cost effectiveness versus alendronate is inconclusive.

Cost-utility analyses of clinical preventive services: published ratios, 1976-1997

BACKGROUND

Cost-effectiveness analyses of clinical preventive services are a potential means to aid public health resource allocation. Cost-utility analysis (CUA) is a specific form of cost-effectiveness analysis where results are expressed in terms of cost per quality-adjusted life year (QALY) gained. To increase the transparency and comparability of CUAs, standardization of methods has been recommended.

OBJECTIVES

The purposes of this study were as follows: (1) identify published articles with original CUAs of primary and secondary clinical preventive services, (2) summarize the ratios found in these analyses, (3) identify articles employing comparable methods, and (4) explore analytic methods employed over time.

METHODS

As part of a larger study we conducted a comprehensive search of published CUAs in the area of clinical preventive services and systematically collected data on the results of the analyses and analytic methods employed. Cost-effectiveness ratios were standardized and organized into a table.

RESULTS

We found 50 CUAs pertaining to clinical preventive services (primary, n=22, 44%; and secondary, n=28, 56%) and 174 cost-effectiveness ratios. These ratios ranged from cost-savings up to $27,000,000/QALY, with a median of $14,000/QALY. Only three (6%) of the CUAs met minimum reference case requirements. There was no apparent improvement of methods over time.

CONCLUSIONS

Immunizations and chemoprophylaxis have the most favorable cost-effectiveness ratios, and preventive services are more cost-effective when targeted at high-risk populations. However, there is wide variation in the methods used in these analyses. This study allows us to define where improvements in methodologic rigor need to occur, provides a base-line for future audits, and highlights disease areas in clinical preventive services that have been omitted or underevaluated.

Assessing quality in decision analytic cost-effectiveness models. A suggested framework and example of application

Despite the growing use of decision analytic modelling in cost-effectiveness analysis, there is a relatively small literature on what constitutes good practice in decision analysis. The aim of this paper is to consider the concept of 'validity' and 'quality' in this area of evaluation, and to suggest a framework by which quality can be demonstrated on the part of the analyst and assessed by the reviewer and user. The paper begins by considering the purpose of cost-effectiveness models and argues that the their role is to identify optimum treatment decisions in the context of uncertainty about future states of the world. The issue of whether such models can be defined as 'scientific' is considered. The notion that decision analysis undertaken at time t can only be considered scientific if its outputs closely predict the results of a trial undertaken at time t + 1 is rejected as this ignores the need to make decisions on the basis of currently available evidence. Rather, the scientific characteristic of decision models is based on the fact that, in principle at least, such analyses can be falsified by comparison of two states of the world, one where resource allocation decisions are based on formal decision analysis and the other where such decisions are not. This section of the paper also rejects the idea of exact codification of scientific method in general, and of decision analysis in particular, as this risks rejecting potentially valuable models, may discourage the development of novel methods and can distort research priorities. However, the paper argues that it is both possible and necessary to develop a framework for assessing quality in decision models. Building on earlier work, various dimensions of quality in decision modelling are considered: model structure (disease states, options, time horizon and cycle length); data (identification, incorporation, handling uncertainty); and consistency (internal and external). Within this taxonomy a (nonexhaustive) list of questions about quality is suggested which are illustrated by their application to a specific published model. The paper argues that such a framework can never be prescriptive about every aspect of decision modelling. Rather, it should encourage the analyst to provide an explicit and comprehensive justification of their methods, and allow the user of the model to make an informed judgment about the relevance, coherence and usefulness of the analysis.

Testing the validity of cost-effectiveness models

A growing body of recent work has identified several problems with economic evaluations undertaken alongside controlled trials that can have potentially serious impacts on the ability of decision makers to draw valid conclusions. At the same time, the use of cost-effectiveness models has been drawn into question, due to the alleged arbitrary nature of their construction. This has led researchers to try and identify ways of improving the quality of cost-effectiveness models through identifying 'best practice', producing guidelines for peer review and identifying tests of validity. This paper investigates the issue of testing the validity of cost-effectiveness models or, perhaps more appropriately, whether it is possible to objectively measure the quality of a cost-effectiveness model. A review of the literature shows that there is much confusion over the different aspects of modelling that should be assessed in respect to model quality, and how this should be done. We develop a framework for assessing model quality in terms of: (i) the structure of the model; (ii) the inputs of the model; (iii) the results of the model; and (iv) the value of the model to the decision maker. Quality assessment is investigated within this framework, and it is argued that it is doubtful that a set of objective tests of validity will ever be produced, or indeed that such an approach would be desirable. The lack of any clearly definable and objective tests of validity means that the other parts of the evaluation process need to be given greater emphasis. Quality assurance forms a small part of a broader process and is best implemented in the form of good practice guidelines. A set of key guidelines are presented.

Has the impact of hormone replacement therapy on health-related quality of life been undervalued?

Previous economic evaluations of hormone replacement therapy (HRT) have restricted positive effects to alleviation of postmenopausal symptoms and negative effects to drug side effects. We studied the association between HRT use and postmenopausal women's valuation of both health-related quality of life and potential treatment side effects. Postmenopausal women with either a documented first vertebral fracture within the past 5 years or no history of osteoporotic fractures were recruited from Olmsted County, Minnesota, and from Dartmouth-Hitchcock Medical Center in New Hampshire to participate in a study to assess quality of life and women's attitudes toward osteoporosis prevention. Women's valuations of their current health and potential HRT-related side effects were quantified as quality-adjusted life years (QALYs) assessed by an automated utility assessment instrument (U-Titer) and the time tradeoff technique, by a vertical rating scale, and by estimated quality of well-being (QWB) scores. Health status was measured using the Medical Outcomes Study SF-36. Regression methods were used to assess the impact of current HRT use on health-related quality of life and valuation of side effects. There were 106 women with vertebral fracture and 180 with no history of hip, wrist, or vertebral fractures. Altogether, 116 (40.6%) women were currently taking HRT, 64 (22.2%) had taken HRT in the past, and 106 (37.1%) women had never taken HRT. Current HRT users had higher time tradeoff QALYs than never and past HRT users, with gains ranging from 15.0 to 83.7 days per year for current users relative to the others. Benefits were largest for women with a vertebral fracture and limitations in activities. The secondary QALY measures also showed significantly higher values for current HRT users compared with other women, as did SF-36 subscales for general health, physical function, role-emotional function, and vitality. There was substantial variability in women's perceptions of HRT side effects. Overall, the proportion of women willing to trade time to avoid bleeding was largest, at 95.5%, followed by breast tenderness, weight gain, and endometrial biopsy at 90.4%, 87.4%, and 82.7%, respectively. Current HRT users had higher health-related quality of life than past or never users according to all measures studied. Women's perceptions of potential side effects were highly variable and should be considered by physicians when prescribing an HRT regimen. If, as our results suggest, postmenopausal therapy has positive effects beyond the immediate postmenopausal years, previous economic studies may have underestimated the value of HRT.

A concise review of the cost-effectiveness of coronary heart disease prevention

Coronary heart disease is one of the largest sources of morbidity, mortality, and health care expenditure in the United States. This article reviews a number of studies that estimate the cost per unit of health benefits associated with different primary and secondary prevention strategies for coronary heart disease. Although prevention does not provide a panacea for rising health care spending, many preventive strategies are cost-effective when compared to other common clinical interventions. Prevention should be incorporated into regular clinical practice.

Determinants of bone loss from the femoral neck in women of different ages

An age-stratified sample of 304 women from Rochester, Minnesota, aged 30-94 years (median 60 years) at baseline underwent measurement of femoral neck bone mineral density (BMD) over a follow-up period extending to 16 years. The average rate of change in femoral neck BMD was -1.0% per year (range -10.0% to +13.4%) and did not vary significantly with age. Because there was no marked increase in the rate of loss around the time of menopause, nor convincing evidence of there being a subset of fast losers, there was fairly good tracking of individual values over time; the correlation of baseline with femoral neck BMD values 16 years later was 0.83. Although a large number of potential determinants was assessed, the only consistent predictor of femoral neck bone loss in women of different ages was baseline femoral neck BMD (r = -0.15; p = 0.023). Otherwise, different sets of risk factors were identified for premenopausal women, women within 20 years of menopause, and women 20 years or more postmenopausal, but the predictive power of these different multivariate models was modest. Nonetheless, these data indicate that femoral neck BMD is quite predictable for extended periods of time. This is reassuring with respect to the use of statistical models that incorporate such data to estimate future fracture risk.

Estimating the population impact of an intervention: a decision-analytic approach

The aim of this paper is to highlight the role for decision analysis in assessing outcomes of medical interventions at a population level. The basic steps of decision analysis are introduced and an illustrative hypothetical preventive intervention is examined. Specific modelling challenges that arise when estimating the population impact of an intervention are described and each is accompanied by an example. Decision analysis can provide useful information for health policy decision makers by identifying the intervention(s) with the largest beneficial impact on health over a wide range of assumptions. In addition, by focusing attention on the parameters with the greatest influence on projected outcomes, decision analysis can aid in identifying critical areas for future research.

Cost-effectiveness analysis of nimodipine treatment after aneurysmal subarachnoid hemorrhage and surgery

OBJECTIVE

To assess the cost-effectiveness ratio of nimodipine administration after aneurysmal subarachnoid hemorrhage (SAH) and surgery.

METHODS

One hundred twenty-seven patients of both sexes who had a ruptured aneurysm (verified using angiography), who presented with Hunt and Hess Grades I to III on admission, who underwent an operation within the first week after SAH, and who had participated in a randomized prospective clinical trial of nimodipine medication were enrolled in the study. The efficiency (cost-effectiveness) of nimodipine treatment was evaluated by incremental cost-effectiveness analysis. The cost-effectiveness ratio was evaluated for two groups: patients treated with nimodipine and patients given placebo. The cost was estimated as direct hospitalization costs, and the patient outcome was measured as life years gained.

RESULTS

The incremental cost-effectiveness ratio for nimodipine treatment was $223 per life year gained on the basis of 1996 monetary values and contemporary management of SAH. Patients in the nimodipine group had an average of 3.46 years longer life expectancy (incremental effectiveness) than those in the placebo group. There was a significant difference in 3-month follow-up mortality and a slight difference in sickness pensions during the 10 years after SAH. Nimodipine treatment was associated with a significant decrease in mortality. There were no statistically significant differences between the treatment groups in the length of hospital stay. There were no statistically significant differences between the treatment groups in sickness pensions.

CONCLUSION

Nimodipine is cost-effective. Therefore, its use in the management of patients with SAH seems economically justified because it increases patient life years at very low incremental cost.

Cost-effectiveness analysis of screening for asymptomatic, unruptured intracranial aneurysms. A mathematical model

BACKGROUND AND PURPOSE

Subarachnoid hemorrhage (SAH) due to aneurysmal rupture is a major cause of cerebrovascular disease-related death. This problem could be eliminated by diagnosis and successful treatment of aneurysms before rupture. Recent developments in high-resolution imaging technology have made screening for unruptured aneurysms possible in the general population. Such screening has become widespread in Japan ("No Dokku, " or brain checkup). As a result, unruptured aneurysms are being identified with increasing frequency. However, the economic implications of treatment decisions for unruptured aneurysms have not been analyzed. Therefore, we performed such an analysis.

METHODS

We used a Markov model to evaluate the cost-effectiveness of screening for asymptomatic, unruptured intracranial aneurysms. The model involved a set of variables describing discrete health states. Each state was assigned a quality of life score and an associated medical cost. A comparison of the expected outcomes was then made between 2 hypothetical cohorts, one receiving screening and the other no screening. A sensitivity analysis was performed by altering the input values within clinically reasonable ranges to reflect uncertainty in the baseline analysis and then assessing the effects on outcomes.

RESULTS

Combining the incremental cost and effectiveness data revealed a cost per quality-adjusted life-year of $7760 for an annual rate of subarachnoid hemorrhage due to unruptured aneurysms (rupture rate) of 0.02; this cost was $39 450 for a rupture rate of 0.01. There was no benefit (negative quality-adjusted life-year benefit) for a rupture rate of 0.005, the rupture rate found in a recently published international cooperative study. The risks of surgery for unruptured aneurysms and the discounting ratio used to assess the impact of timing of costs and benefits on future outcomes also had significant effects on the results. Other variables had little impact on cost-effectiveness.

CONCLUSIONS

The cost-effectiveness of screening for an unruptured aneurysm is highly sensitive to the annual rate of subarachnoid hemorrhage due to unruptured aneurysms. The low annual rupture rate seen in the recent large international cooperative study implies that screening asymptomatic populations to identify and treat unruptured aneurysms would not be cost cost-effective.

The potential effect on hip fracture incidence of mass screening for osteoporosis

With ageing of the Australian population, treatment of osteoporosis-related hip fractures will impose an increasing burden on the healthcare system. Based on current age-adjusted hip fracture incidence and population projections for New South Wales, we estimated a 90% increase in hip fractures by the year 2021. Contributing significantly to this increase will be the number of men reaching the high risk age group for osteoporotic hip fractures. A suggested solution--screening and appropriate therapy for individuals at high risk of osteoporosis--may have only a modest impact. Our calculations show that, even with optimistic screening and therapy compliance rates, hip fractures could still increase by over 50%. Other approaches need to be further explored.

Health-related quality of life in economic evaluations for osteoporosis: whose values should we use?

OBJECTIVE

To determine whether the source of preference scores has an impact on the cost-effectiveness of osteoporosis interventions.

METHODS

Three groups of subjects aged > or =50 years--199 women without fractures and 183 women with osteoporotic fractures-were studied at two major medical centers. Medical history and comorbidity data were obtained from review of medical records. Health status was measured using the Medical Outcomes Study SF-36. Two preference-classification systems (i.e., quality of well-being scores estimated from SF-36 subscales and the Health Utilities Index) were also used. Preferences for current health and for hypothetical health states were assessed using a time tradeoff and implemented with a computer-based utility instrument (U-Titer). Wilcoxon's rank-sum and signed-rank tests were used to compare preferences for current health among women with osteoporotic fractures with 1) directly assessed preferences for osteoporosis health states delineated by outcome descriptions and 2) preference scores obtained from the preference-classification systems. The potential impact of the source of the preference scores was estimated using a Markov state-transition model.

RESULTS

The preference scores for hypothetical osteoporosis health states of the non-fracture subjects were approximately 50% lower than those of the women who had actually experienced the health state. Differences of this magnitude would change the estimated cost-effectiveness of a 15-year intervention (which for approximately $280 per year prevents hip fracture about as well as hormone-replacement therapy) from $25,000 per QALY gained when non-fracture subjects' preferences were used to $94,000 per QALY gained when fracture subjects' preferences were used. Preferences estimated using the Health Utilities Index and those directly measured in fracture subjects using the time tradeoff did not differ significantly.

CONCLUSIONS

The Health Utilities Index preference-classification system may provide an efficient and inexpensive alternative to direct utility assessment in this patient group. However, there are important differences in the valuation of health states by women who have experienced osteoporotic fractures compared with women who have not. Cost-utility analyses based solely on fracture patients' preferences for osteoporotic health states may undervalue prevention.

Performing cost-effectiveness analysis by integrating randomized trial data with a comprehensive decision model: application to treatment of acute ischemic stroke

A recent national panel on cost-effectiveness in health and medicine has recommended that cost-effectiveness analysis (CEA) of randomized controlled trials (RCTs) should reflect the effect of treatments on long-term outcomes. Because the follow-up period of RCTs tends to be relatively short, long-term implications of treatments must be assessed using other sources. We used a comprehensive simulation model of the natural history of stroke to estimate long-term outcomes after a hypothetical RCT of an acute stroke treatment. The RCT generates estimates of short-term quality-adjusted survival and cost and also the pattern of disability at the conclusion of follow-up. The simulation model incorporates the effect of disability on long-term outcomes, thus supporting a comprehensive CEA. Treatments that produce relatively modest improvements in the pattern of outcomes after ischemic stroke are likely to be cost-effective. This conclusion was robust to modifying the assumptions underlying the analysis. More effective treatments in the acute phase immediately following stroke would generate significant public health benefits, even if these treatments have a high price and result in relatively small reductions in disability. Simulation-based modeling can provide the critical link between a treatment's short-term effects and its long-term implications and can thus support comprehensive CEA.

Active detection of chronic obstructive pulmonary disease and asthma in the general population. Results and economic consequences of the DIMCA program

The aim of this prospective study was to detect subjects in the general population with objective signs of chronic obstructive pulmonary disease (COPD) or asthma at an early stage. This was done by means of a two-stage protocol involving screening and a subsequent 2-yr monitoring of all subjects with positive results of screening. The study was done in 10 general practices located in the eastern part of the Netherlands. A random sample was taken from the general population aged 25 to 70 yr. All known COPD and asthma patients were excluded. A total of 1,749 subjects met the inclusion criteria: 1,155 subjects (66%) agreed to participate in the screening stage of the study. A total of 604 subjects (52.3%) showed symptoms or objective signs of COPD or asthma during the screening and were considered "positive." Of those with positive screening results, 384 subjects (64%) agreed to participate in the second, 2-yr monitoring stage of the study. The costs involved in detection were calculated for three different scenarios, as follows: (1) The detection of subjects with persistently decreased lung function or an increased level of bronchial hyperresponsiveness (BHR) during 6 mo of monitoring; (2) Scenario 1 plus the detection of subjects with a rapid decline in lung function with signs of BHR during 12 mo of monitoring; (3) Scenario 2 plus the detection of subjects with a moderate increase in the decline in lung function or signs of BHR during 24 mo of monitoring. The costs of lung function assessments, organization, transportation, and patient time were included. The costs were converted to United States dollars on the basis of purchasing power (1 United States dollar = 2.08 Netherlands guilders). During the second stage, 252 subjects were detected with objective signs of COPD or asthma at an early stage. Smoking status as a screening criterion was neither sensitive nor specific. Because there was no evidence of biased recruitment or selection during the program, the proportions of subjects found to have objective signs of COPD or asthma at an early stage could be extrapolated to the general population. Of the general population, 7.7% showed persistently reduced lung function or increased BHR. Another 12.5 % of the general population showed a rapid decline in lung function (> 80 ml/yr) in combination with signs of BHR, and a further 19.4% of the general population showed mild objective signs of COPD or asthma. The average costs per detected case varied from US$953 (Scenario 1) to US$469 (Scenario 3). In conclusion, detection of COPD or asthma at an early stage by means of a two-stage protocol was feasible at relatively little expense in comparison with other mass screening programs. Persistently decreased lung function or a rapid decline in lung function (Scenario 2) was observed in approximately 20% of the general adult population.

Does growth hormone therapy in adult patients with growth hormone deficiency protect against bone loss?

Fracture incidence is increased in growth hormone deficiency (GHD). However, the efficacy of growth hormone (GH) in the prevention of fractures in GHD is not documented. GH is important to attain normal peak bone mass; it increases bone mass in children and adolescents, but is less important with increasing age and is insignificant above the age of 55-60 years old. Placebo-controlled trials of 12 months' duration have failed to improve bone mass density, while uncontrolled studies have suggested that GH treatment for 2-4 years may increase bone mass by 0.5 of a standard deviation in adults. Given the current high price of GH treatment, however, routine substitution with the intention to decrease fracture incidence in adult GHD patients is not likely to be cost effective. GH substitution should probably be extended until peak bone mass has been achieved, and repeated dual energy X-ray scan measurements with intervals of 1-2 years could be helpful in deciding when to stop treatment.

Risk assessment for osteoporosis using bone mineral density determination: a belgian perspective

The availability of bone densitometry in daily clinical practice has revolutionized the capacity to detect osteoporosis, to estimate the risk of future fracture, and to select those patients who are likely to benefit most from preventive or therapeutic measures. In spite of the high availability of densitometry in Belgium and the high incidence of risk factors for osteoporosis in elderly women, osteoporosis is presumably underdiagnosed. It is likely that the limited use of widely available technology to evaluate osteoporosis results from a complex interaction of numerous factors, some of which are discussed. In spite of many unanswered questions, the main conclusion to be drawn from the Belgian experience is that a high density of densitometry facilities is no guarantee that the majority of women who are at greatest risk of fracture will actually become the focus of preventive measures or therapy.