Under its Evidence-based Practice Program, the Agency for Healthcare Research and Quality (AHRQ) is developing scientific information for other agencies and organizations on which to base clinical guidelines, performance measures, and other quality improvement tools. Contractor institutions review all relevant scientific literature on assigned clinical care topics and produce evidence reports and technology assessments, conduct research on methodologies and the effectiveness of their implementation, and participate in technical assistance activities.
Overview / Reporting the Evidence / Methodology / Findings / Future Research / Availability of Full Report
At an international consensus development conference, osteoporosis was defined as "a systemic skeletal disease characterized by low bone mass and microarchitectural deterioration of bone tissue, leading to enhanced bone fragility and a consequent increase in fracture risk." In 1994, a World Health Organization (WHO) working group proposed that, in epidemiologic studies, osteoporosis could be determined when bone density at the hip, spine, or forearm is 2.5 standard deviations or more below the mean for healthy, young, adult women (a value defined as the T-score), or when a history of a fracture is present in the absence of trauma. The group also proposed that osteopenia be determined when the bone density was 1.0 to 2.5 standard deviations below the mean for young, healthy women.
According to the National Health and Nutrition Examination Survey (NHANES III), an estimated 14 million American women over age 50 years are affected by low bone density at the hip, and 5 million more have bone density that measures 2.5 standard deviations or more below the mean at the hip. The prevalence of osteoporosis in Mexican-American women is similar to that in white women, while rates in black women are approximately half that of the first two groups. The prevalence of osteoporosis increases with age for all sites, and by the WHO definition up to 70 percent of women over age 80 years have osteoporosis.
Furthermore, age is an important factor in the relationship between bone density and the absolute risk of fracture. An increase in age of 13 years increases the risk of hip fracture by the same amount as a decrease in bone density of one standard deviation. Older women have a much higher fracture rate than younger women who have the same bone density, because of increasing risk from other factors, such as a change in bone quality and the tendency to fall.
Women with osteoporosis are more likely to experience fractures. Demographic trends for hip fracture parallel those for osteoporosis. Hip-fracture incidence in white women rises from 50 per 100,000 at age 50 years to 237 per 100,000 at age 65 years. White women are generally two to three times more likely than nonwhite women to suffer a hip fracture. Hip fractures are associated with high rates of mortality and loss of independence. Wrist fracture incidence tends to increase at earlier ages than does that of hip fractures.
Vertebral fractures have also been associated with significant morbidity. Sixteen percent of postmenopausal women have osteoporosis of the lumbar spine; furthermore, five percent of 50-year-old white women and 25 percent of 80-year-old women have had at least one vertebral fracture. Vertebral fractures can cause severe pain and are associated with more than five million days of restricted activity in those age 45 years or older.
The disease burden of osteoporosis extends beyond consequences of low bone density and fractures. For example, the act of screening, diagnosis, and subsequent treatment can also affect the quality of life. Fear of fracture itself can reduce the quality of life in women who have been diagnosed as having osteoporosis.
In 1995, the total direct medical expenditure in the United States for the treatment of osteoporotic fractures in adults older than 45 years was estimated at $13.8 billion. The majority of this total ($8.6 billion) was spent for inpatient care. Hip fracture alone accounted for $8.7 billion (63 percent) of osteoporosis-related costs, while fractures at sites other than the hip accounted for approximately 37 percent of the total expenditure (about $5.1 billion). In addition to these costs is the cost of lost productivity for women with fractures, or for their family or other caregivers. As the median age of the U.S. population increases, the costs associated with osteoporotic fractures are also likely to increase.
This evidence report describes the effectiveness of various strategies for diagnosing and monitoring postmenopausal women with osteoporosis, as represented by six topic areas:
These topic areas do not include the effectiveness of dietary, lifestyle, hormonal, and medical interventions for primary prevention or treatment of osteoporosis.
This report is confined to diagnostic and monitoring strategies as they apply to individual women, and does not include issues regarding mass screening in the general population. Also, while most of the literature addressing these topic areas is aimed at an audience of clinical researchers who specialize in osteoporosis, we have attempted to assess the research findings from the perspectives of clinicians and patients. However, it is not the purpose of this report to propose practice recommendations.
With input from local and national experts, we developed analytic frameworks and key questions in each of the six topic areas. Relevant studies were identified from multiple searches of MEDLINE (for the years 1966 to 2000) and HealthSTAR (for the years 1975 to 2000), from the reference lists of systematic review articles, and from national experts. All searches were limited to publications in the English language. The authors excluded articles if they did not provide sufficient information to determine the methods for selecting subjects and for analyzing data.
Out of 10,174 citations retrieved for all topics combined, the authors selected as possibly relevant 530 articles about risk factors, 123 about bone measurement tests, 23 about bone density monitoring, 277 about biochemical markers, and 53 about costs. An additional 242 studies were retrieved after reviewing reference lists of studies and by suggestion of the expert panel or leading researchers in the field. The search yielded no papers with data for the secondary causes topic, but this topic was addressed by reviewing published guidelines and by a supplemental analysis of physician practice patterns for the evaluation of secondary causes of osteoporosis.
For articles that were included, the authors applied criteria proposed by the U.S. Preventive Services Task Force to rate the quality of individual studies. A second supplemental analysis investigated the cost-effectiveness of various diagnostic strategies.
Relevant articles were reviewed. The findings about the clinical risk factors that predict bone density, bone loss, and fractures included:
A second set of findings about risk factors concerned the accuracy of the sets of clinical questions (typically called instruments, tools, or profiles) used in assessing the risk factors that identify women at risk of fracture. These included:
A third set of findings, exploring whether risk factors are useful in treatment decisions, included:
The major findings related to the capacity of different bone measurement tests to predict fractures included:
Major findings on identification of the factors related to bone testing that influence diagnosis included:
Major findings related to how bone measurement test results affect patients' and physicians' decisions and actions included:
The major findings regarding whether bone measurement tests are effective for monitoring response to therapy and for guiding decisions about changes in management included:
Findings regarding whether biochemical markers can be used instead of bone measurement tests to identify women who have low bone density included:
Major findings as to how well biochemical markers predict fracture included:
In addition, major findings as to whether markers can help select patients for treatment included:
Major findings regarding whether markers can predict a patients' response to therapy included:
Major findings from a literature review, assessment of published guidelines, and a secondary analysis regarding which diagnostic or laboratory tests are appropriate for evaluating patients with osteoporosis for secondary causes included:
The reports' findings regarding the costs and cost-effectiveness of diagnostic strategies for identifying women with osteoporosis included:
Much of the evidence for the diagnosis and monitoring strategies for osteoporosis comes from epidemiologic studies. To be more useful for clinicians and patients, future research should focus on the application of these data to the clinical setting and include a wider diversity of patient populations. Tools for assessing risk factors should be tested in prospective studies to determine if their use can correctly stratify women by risk factors, influence treatment decisions, and ultimately reduce fracture outcomes.
Clinical trials should be conducted to determine if identifying and reducing modifiable risk factors influences fracture outcomes. Addressing some of these modifiable risk factors, such as by supplementation with calcium and vitamin D, has already demonstrated effects on fracture risk after intervention. Examples of additional interventions to test include smoking cessation, correcting visual loss, and improving physical function.
Future research should examine the clinical utility of the WHO working group's criterion for diagnosing osteoporosis. Randomized, controlled trials of treatments for osteoporosis should be done to test the hypothesis that overall fracture risk, rather than bone measurement results alone, determines the likelihood that a patient will benefit from therapy. Trials should also address whether patients who are identified to have bone loss demonstrated by different techniques at different anatomical sites demonstrate a similar benefit to those identified solely by hip DXA measurements.
Additional research is needed to examine the quality of information provided to patients who undergo various bone measurement tests, as well as to identify other patient education and information needs.
Studies that use bone measurement tests for monitoring response to therapy could compare fracture outcomes in a group of patients who had tailored therapy based on test results versus a group in whom changes in therapy, if any, were guided by the history alone. A study could also record how often test results in patients on therapy led to a change in therapy or improved compliance, to establish the mechanism by which monitoring leads to improved fracture outcomes.
Prospective studies of biochemical markers should define, apply, and evaluate criteria for using marker results in clinical decisionmaking.
Determining the utility of screening for secondary disorders by use of common laboratory tests requires studies of the frequency of abnormal baseline laboratory test results in large cohorts or in treatment trials of osteoporosis. Clinical follow-up of these subjects would provide data on bone measurement test results or fracture outcomes.
Studies to formally account for the adverse quality-of-life impact of treatment and treatments side effects are needed to more accurately determine the balance of risks and benefits of the therapy options presented to patients.
Additional cost-effectiveness research could include identifying a scientifically appropriate cut point for QUS/BUA that can be used in a sequential diagnostic approach or for diagnosis with QUS alone. Performing additional cost-effectiveness analyses using data from other large, population-based cohorts with various cut points and conducting a more detailed, societal-perspective, cost-effectiveness analysis would address some of the deficiencies in the authors' analysis. If these findings can be demonstrated in one or two other populations, and in a more complete economic evaluation, a randomized, controlled trial of diagnostic approaches would be a useful next step.
The full evidence report from which this summary was derived was prepared for the Agency for Healthcare Research and Quality by the Oregon Health Sciences University Evidence-based Practice Center under contract No. 290-97-0018. Printed copies may be obtained free of charge from the AHRQ Publications Clearinghouse by calling 800-358-9295. Requestors should ask for Evidence Report/Technology Assessment No. 28, Osteoporosis in Postmenopausal Women: Diagnosis and Monitoring (AHRQ Publication No. 01-E032).
The Evidence Report is also online on the National Library of Medicine Bookshelf, or can be downloaded as a zipped file.
AHRQ Publication Number 01-E031
Current as of February 2001
Internet Citation:
Osteoporosis in Postmenopausal Women: Diagnosis and Monitoring. Summary, Evidence Report/Technology Assessment: Number 28. AHRQ Publication Number 01-E031, February 2001. Agency for Healthcare Research and Quality, Rockville, MD. http://www.ahrq.gov/clinic/epcsums/osteosum.htm
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