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Bone Mineral Density Testing in Clinical Practice Screen & Intervene Critical Challenges in Osteoporosis and Womens Health.

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Presentation on theme: "Bone Mineral Density Testing in Clinical Practice Screen & Intervene Critical Challenges in Osteoporosis and Womens Health."— Presentation transcript:

1 Bone Mineral Density Testing in Clinical Practice Screen & Intervene Critical Challenges in Osteoporosis and Womens Health

2 Outline Background Background Diagnosis of osteoporosis Diagnosis of osteoporosis BMD and fracture risk BMD and fracture risk Indications for BMD testing Indications for BMD testing Interpretation of BMD tests Interpretation of BMD tests Combining BMD and clinical risk factors Combining BMD and clinical risk factors Selecting patients for treatment Selecting patients for treatment Serial BMD testing Serial BMD testing Peripheral bone density testing Peripheral bone density testing

3 Osteoporosis is a Silent Disease No symptoms No symptoms No findings on physical exam No findings on physical exam No laboratory abnormalities No laboratory abnormalities Increase in fracture risk Increase in fracture risk –Fractures have serious consequences –Treatment can reduce fracture risk Challenge: To identify and treat patients at risk for fracture before the first fracture occurs

4 Consequences of Fractures Increased risk of future fractures Increased risk of future fractures Chronic pain Chronic pain Surgery Surgery Loss of height Loss of height Impaired pulmonary function Impaired pulmonary function Abdominal symptoms Abdominal symptoms Medical expenses / lost income Medical expenses / lost income Hospitalization Surgery Rehab hospital Nursing home Loss of self-esteem Depression Loss of independence Disability Death

5 Relative Risk of Death Following Clinical Fractures Age-Adjusted Relative Risk (95% CI) Any Symptomatic Nonspine Other Forearm Spine Hip Fracture Intervention Trial (FIT): 6459 postmenopausal women aged years followed for an average of 3.8 years Cauley JA et al. Osteoporos Int. 2000;11:

6 Diagnosis of Osteoporosis Densitometric Diagnosis Densitometric Diagnosis –Dual-energy X-ray absorptiometry (DXA) –World Health Organization (WHO) criteria Clinical Diagnosis Clinical Diagnosis –Fragility fracture

7 What DXA measures: bone mineral content (BMC) in grams & area in cm 2 Areal BMD is calculated in g/cm 2 (aBMD = BMC/Area) Areal BMD is calculated in g/cm 2 (aBMD = BMC/Area) T-score is calculated using the patients BMD and a reference database T-score is calculated using the patients BMD and a reference database

8 Calculation of T-score Patients BMD – Young-Adult Mean BMD SD of Young-Adult BMD in g/cm 2 Example: T-score = 0.7 g/cm g/cm g/cm 2 = - 3.0

9 WHO Classification of BMD ClassificationT-score Normal -1.0 or greater Low Bone Mass (Osteopenia) Between -1.0 and -2.5 Osteoporosis -2.5 and below Severe Osteoporosis -2.5 and below with history of fragility fracture WHO Study Group 1994.

10 Why is a T-score of -2.5 or less used to diagnose osteoporosis? Such a cutoff value identifies approximately 30% of postmenopausal women as having osteoporosis using measurements made at the spine, hip or forearm. This is approximately equivalent to the lifetime risk of fracture at these sites. Kanis JA et al. J Bone Miner Res. 1994;9:1137.

11 L1-L4 T-score = -2.6

12 Left Femoral Neck T-score = -2.6

13 Use Clinical Judgment T-score greater than -2.5 does not eliminate the possibility of osteoporosis T-score greater than -2.5 does not eliminate the possibility of osteoporosis –Clinical diagnosis of osteoporosis may be made in the presence of a fragility fracture T-score -2.5 or less does not always mean that osteoporosis is present T-score -2.5 or less does not always mean that osteoporosis is present –Primary disease may be something else (e.g., osteomalacia, multiple myeloma)

14 DXA is the Gold Standard Widely used in epidemiological studies from which prevalence data is derived Widely used in epidemiological studies from which prevalence data is derived WHO criteria based on BMD measured by DXA WHO criteria based on BMD measured by DXA Correlation with fracture risk Correlation with fracture risk Low radiation Low radiation Excellent precision Excellent precision

15 Clinical Uses of DXA Diagnose osteoporosis Diagnose osteoporosis Predict fracture risk Predict fracture risk Monitor changes in BMD Monitor changes in BMD

16 Indications for BMD Testing Screening Screening –Women aged 65 and older. –Men aged 70 and older. Risk Factors Risk Factors –Postmenopausal women under age 65 with risk factors. –Adults with a fragility fracture. –Adults with a disease or condition associated with low bone mass or bone loss. –Adults taking medications associated with low bone mass or bone loss. Treatment Treatment –Anyone being considered for pharmacologic therapy. –Anyone being treated, to monitor treatment effect. –Anyone not receiving therapy in whom evidence of bone loss would lead to treatment. Women discontinuing estrogen should be considered for bone density testing according to the indications listed above. Official Position

17 Bone Mass Measurement Act, 7/1/98 Estrogen-deficient women at clinical risk for osteoporosis Estrogen-deficient women at clinical risk for osteoporosis Individuals with vertebral abnormalities Individuals with vertebral abnormalities Individuals receiving long-term glucocorticoid therapy Individuals receiving long-term glucocorticoid therapy Individuals with primary hyperparathyroidism Individuals with primary hyperparathyroidism Individuals being monitored to assess the response to or efficacy of an FDA-approved osteoporosis drug therapy Individuals being monitored to assess the response to or efficacy of an FDA-approved osteoporosis drug therapy Federal Register, Volume 63, Number 121, June 24, Five Categories of Medicare Covered Services

18 Diagnosis in Postmenopausal Women and in Men Age 50 and Older Osteoporosis may be diagnosed in postmenopausal women and in men age 50 and older if the T-score of the lumbar spine, total hip or femoral neck is -2.5 or less:* Osteoporosis may be diagnosed in postmenopausal women and in men age 50 and older if the T-score of the lumbar spine, total hip or femoral neck is -2.5 or less:* –In certain circumstances the 33% radius (also called 1/3 radius) may be utilized. *Note: Other hip regions of interest, including Wards area and the greater trochanter, should not be used for diagnosis. Application of recommendation may vary according to local requirements. Official Position

19 Diagnosis in Premenopausal Women and Men Younger than Age 50 Z-scores, not T-scores are preferred. This is particularly important in children. Z-scores, not T-scores are preferred. This is particularly important in children. A Z-score of -2.0 or lower is defined as below the expected range for age and a Z-score above -2.0 is within the expected range for age. A Z-score of -2.0 or lower is defined as below the expected range for age and a Z-score above -2.0 is within the expected range for age. Official Position

20 Bone Density and Fracture Risk Bone Density (T-score) Relative Risk for Fracture Adapted from Faulkner KG. J Bone Miner Res. 2000;15:

21 Age is an Independent Risk Factor for Fracture Adapted from Kanis JA et al. Osteoporosis Int. 2001;12: Ten Year Fracture Probability (%) Age Probability of first fracture of hip, distal forearm, proximal humerus, and symptomatic vertebral fracture in women of Malmö, Sweden.

22 Predicting Hip Fractures: Relative Risk vs. Fracture Probability (a) Marshall D et al. BMJ. 1996;32: (b) Kanis JA et al. Osteoporos Int. 2001;12: Age* Hip T-score Relative Risk (a) (2.6) Year Probability (b) % % Relative Risk = (RR per SD) T-score or Z-score Difference 10-Year Probability from Swedish National Bureau of Statistics *Postmenopausal Woman

23 Prior Fracture Increases Relative Risk of Subsequent Fractures Klotzbuecher CM et al. J Bone Miner Res. 2000;15: Site of Subsequent Fracture Site of Prior Fracture WristVertebraHip Wrist Vertebra HipNA2.52.3

24 BMD and Clinical Risk Factors Predict Hip Fractures Risk Factors Age 80 Family Hx Hip Fx Any Fx Except Hip Since Age 50 Fair, Poor or Very Poor Health Hx Hyperthyroidism Anticonvulsant Therapy Current Benzodiazepine Rx Current Weight < Age 25 Weight Caffeine > 2 Cups Coffee per Day On Feet 4 hours per Day No Walking for Exercise Cant Rise From Chair Without Using Arms Lowest Quartile Depth Perception Lowest Quartile Contrast Sensitivity Heart Rate > 80 Cummings SR et al. N Engl J Med. 1995;332: Calcaneal Bone Density No. of Risk Factors Rate of Hip Fracture (per 1000 woman-years) SOF in 9516 white women over age 65 with no previous hip fracture

25 NOF Treatment Guidelines Initiate therapy to reduce fracture risk in women with –T-Score less than -2.0, regardless of risk factors –T-Score less than -2.0, regardless of risk factors –T-score between -1.5 and -2.0, if at least one risk factor is present –Previous vertebral or hip fracture Physicians Guide to Prevention and Treatment of Osteoporosis. National Osteoporosis Foundation Major risk factors = fracture as an adult, first degree relative with fragility fracture, weight less than 127 lbs., current smoking, glucocorticoid therapy more than 3 mo.

26 Most Fractures Occur in Patients with T-score Greater Than -2.5 Study of Osteoporotic Fractures (SOF) Study of Osteoporotic Fractures (SOF) –8,065 postmenopausal women age 65 or older –54% of women with hip fracture had baseline T-scores greater than -2.5 (total hip) National Osteoporosis Risk Assessment (NORA) National Osteoporosis Risk Assessment (NORA) –149,524 postmenopausal women with mean age of 65 –82% of 2,259 women with fragility fractures had baseline T-scores greater than -2.5 (peripheral) Wainwright SA et al. J Clin Endocrinol Metab. 2005;90: Siris ES et al. Arch Intern Med. 2004;164:

27 WHO Project Goal: To develop a standardized methodology for expressing fracture risk and intervention thresholds for men and women worldwide Goal: To develop a standardized methodology for expressing fracture risk and intervention thresholds for men and women worldwide Method: Study correlations of BMD and clinical risk factors with fracture outcomes in large prospective observational studies, and apply cost utility analysis to set intervention thresholds Method: Study correlations of BMD and clinical risk factors with fracture outcomes in large prospective observational studies, and apply cost utility analysis to set intervention thresholds

28 Fracture Risk Reporting Since the goal of osteoporosis therapy is fracture prevention, patient selection is best based on fracture risk Since the goal of osteoporosis therapy is fracture prevention, patient selection is best based on fracture risk T-score alone does not provide a complete assessment of fracture risk T-score alone does not provide a complete assessment of fracture risk Combination of clinical risk factors with BMD may provide a better way of identifying patients for treatment Combination of clinical risk factors with BMD may provide a better way of identifying patients for treatment

29 Selection of Clinical Risk Factors Independent of BMD (if BMD is known) Independent of BMD (if BMD is known) Validated in multiple populations (sex, ethnicity, country) Validated in multiple populations (sex, ethnicity, country) Easily obtainable Easily obtainable Amenable to intended treatment Amenable to intended treatment Intuitive Intuitive Adapted from Kanis JA et al. Osteoporos Int. 2005;16:

30 Clinical Risk Factors Femoral neck T-score + Age Age Previous low trauma fracture Previous low trauma fracture Current cigarette smoking Current cigarette smoking Rheumatoid arthritis Rheumatoid arthritis High alcohol intake (> 2 units/day) High alcohol intake (> 2 units/day) Parental history of hip fracture Parental history of hip fracture Prior or current glucocorticoid use Prior or current glucocorticoid use Adapted from Kanis JA et al. Osteoporos Int. 2005;16:

31 Intervention Threshold A fracture probability above which it is cost-effective to treat with pharmacological agents A fracture probability above which it is cost-effective to treat with pharmacological agents Based on statistical modeling using many medical, social, and economic assumptions Based on statistical modeling using many medical, social, and economic assumptions

32 Decision to Treat Fracture probability Fracture probability Cost-effectiveness Cost-effectiveness Efficacy Efficacy Safety Safety Expected adherence to therapy Expected adherence to therapy Non-skeletal risks and benefits Non-skeletal risks and benefits Patient beliefs and preferences Patient beliefs and preferences

33 Why do serial BMD testing? To monitor response to therapy by finding an increase or stability of bone density, and To monitor response to therapy by finding an increase or stability of bone density, and To evaluate for non-response by finding loss of bone density- suggesting the need for re-evaluation of treatment and evaluation for secondary causes of osteoporosis To evaluate for non-response by finding loss of bone density- suggesting the need for re-evaluation of treatment and evaluation for secondary causes of osteoporosis J Clin Densitom. 2002;5(Suppl):S1-S45.

34 When should repeat BMD testing be done? When expected change in BMD equals or exceeds the Least Significant Change (LSC) When expected change in BMD equals or exceeds the Least Significant Change (LSC) Intervals between BMD testing should be determined according to each patients clinical status Intervals between BMD testing should be determined according to each patients clinical status –Consider 1 year after initiation or change of therapy –Longer intervals once therapeutic effect is established –Shorter intervals when rapid bone loss is expected J Clin Densitom. 2002;5(Suppl):S1-S45.

35 Always Compare BMD Never Compare T-scores

36 BMD Values from Different Manufacturers are Not Comparable Different dual energy methods Different dual energy methods Different calibration Different calibration Different detectors Different detectors Different edge detection software Different edge detection software Different regions of interest Different regions of interest

37 Vertebral Fracture Assessment (VFA) Recognition of vertebral fracture may 1. Change diagnostic classification 2. Change estimate of fracture risk 3. Change treatment decisions NormalVertebral Fx

38 Peripheral Measuring Devices

39 Peripheral Bone Density Measurement Good prediction of fracture risk Good prediction of fracture risk Good tool for skeletal health education Good tool for skeletal health education Cannot be used with the WHO criteria for diagnosis of osteoporosis Cannot be used with the WHO criteria for diagnosis of osteoporosis Not useful for monitoring bone density changes Not useful for monitoring bone density changes J Clin Densitom. 2002;5(Suppl):S1-S45.

40 Summary BMD testing can diagnose osteoporosis, predict fracture risk, and monitor changes in BMD over time BMD testing can diagnose osteoporosis, predict fracture risk, and monitor changes in BMD over time Combination of BMD and clinical risk factors is as better predictor of fracture risk than BMD or clinical risk factors alone Combination of BMD and clinical risk factors is as better predictor of fracture risk than BMD or clinical risk factors alone Patients at high risk for fracture are most likely to benefit from therapy Patients at high risk for fracture are most likely to benefit from therapy


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