Download Management of Vertebral Compression Fractures

Bone Mineral Density Testing
in Clinical Practice
Screen & Intervene
Critical Challenges in Osteoporosis and Women’s Health
Outline
► Background
► Diagnosis
of osteoporosis
► BMD and fracture risk
► Indications for BMD testing
► Interpretation of BMD tests
► Combining BMD and clinical risk factors
► Selecting patients for treatment
► Serial BMD testing
► Peripheral bone density testing
Osteoporosis is a Silent Disease
► No
symptoms
► No findings on physical exam
► No laboratory abnormalities
► 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
Consequences of Fractures
►
Increased risk of future
fractures
►
Chronic pain
►
Surgery
►
Loss of height
►
Impaired pulmonary
function
►
Hospitalization
►
Surgery
►
Rehab hospital
►
Nursing home
►
Loss of self-esteem
►
Depression
►
Abdominal symptoms
►
Loss of independence
►
Medical expenses / lost
income
►
Disability
►
Death
Relative Risk of Death
Following Clinical Fractures
Fracture Intervention Trial (FIT):
6459 postmenopausal women
aged 55-81 years followed for an
average of 3.8 years
Any Symptomatic
Nonspine
6.7
Hip
8.6
Spine
Forearm
Other
0.3
1.0
2.0
5.0 10.0 16.0
Age-Adjusted Relative Risk (95% CI)
Cauley JA et al. Osteoporos Int. 2000;11:556-561.
Diagnosis of Osteoporosis
► Densitometric
Diagnosis
– Dual-energy X-ray absorptiometry (DXA)
– World Health Organization (WHO) criteria
► Clinical
Diagnosis
– Fragility fracture
WHO Classification of BMD
Classification
T-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.
L1-L4 T-score = -2.6
Left Femoral Neck T-score = -2.6
Use Clinical Judgment
► 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
– Primary disease may be something else
(e.g., osteomalacia, multiple myeloma)
DXA is the “Gold Standard”
► Widely
used in epidemiological studies
from which prevalence data is derived
► WHO criteria based on BMD measured
by DXA
► Correlation with fracture risk
► Low radiation
► Excellent precision
Clinical Uses of DXA
► Diagnose
► Predict
► Monitor
osteoporosis
fracture risk
changes in BMD
Official Position
►
Indications for BMD Testing
Screening
– Women aged 65 and older.
– Men aged 70 and older.
►
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
– 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.
Bone Mass Measurement Act,
7/1/98
Five Categories of Medicare Covered Services
►
Estrogen-deficient women at clinical risk for
osteoporosis
► Individuals with vertebral abnormalities
► Individuals receiving long-term glucocorticoid
therapy
► Individuals with primary hyperparathyroidism
► 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, 1998.
Official Position
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:*
– In certain circumstances the 33% radius
(also called 1/3 radius) may be utilized.
*Note: Other hip regions of interest, including Ward’s area and the
greater trochanter, should not be used for diagnosis. Application of
recommendation may vary according to local requirements.
Diagnosis in Premenopausal Women
and Men Younger than Age 50
Official Position
► 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.”
Bone Density and Fracture Risk
35
30
25
Relative Risk 20
for Fracture
15
10
5
0
1.0
0.0
-1.0
-2.0
-3.0
Bone Density (T-score)
Adapted from Faulkner KG. J Bone Miner Res. 2000;15:183-187.
-4.0
-5.0
Age is an Independent Risk Factor
for Fracture
Age
50
Ten Year
Fracture
Probability
(%)
40
80
70
30
60
20
50
10
0
1.0
0.5
0.0
-0.5
-1.0
-1.5
-2.0
-2.5
-3.0
-3.5
Femoral Neck T-score
Probability of first fracture of hip, distal forearm,
proximal humerus, and symptomatic vertebral fracture in
women of Malmö, Sweden.
Adapted from Kanis JA et al. Osteoporosis Int. 2001;12:989-995.
-4.0
Predicting Hip Fractures:
Relative Risk vs. Fracture Probability
Age*
Hip T-score
Relative Risk (a)
(2.6)2.5
10-Year
Probability (b)
50
-2.5
17.6
1.9%
80
-2.5
17.6
19.4%
Relative Risk = (RR per SD)T-score or Z-score Difference
10-Year Probability from Swedish National Bureau of Statistics
*Postmenopausal Woman
(a) Marshall D et al. BMJ. 1996;32:1254-1259.
(b) Kanis JA et al. Osteoporos Int. 2001;12:417-427.
Prior Fracture Increases Relative
Risk of Subsequent Fractures
Site of Subsequent Fracture
Site of Prior Fracture
Wrist
Vertebra
Hip
Wrist
3.3
1.7
1.9
Vertebra
1.4
4.4
2.3
Hip
NA
2.5
2.3
Klotzbuecher CM et al. J Bone Miner Res. 2000;15:721-739.
BMD and Clinical Risk Factors
Predict Hip Fractures
Risk Factors
Age ≥ 80
27.3
Family Hx Hip Fx
(per 1000 woman-years)
Rate of Hip Fracture
Any Fx Except Hip Since Age 50
Fair, Poor or Very Poor Health
30
Hx Hyperthyroidism
14.7
25
20
Current Benzodiazepine Rx
Current Weight < Age 25 Weight
15
5.6
4.0
10
5
Anticonvulsant Therapy
9.4
2.6
>4
1.9
1.1
0
1.1
Lowest Third Middle Third Highest Third
Calcaneal Bone Density
SOF in 9516 white women over age
65 with no previous hip fracture
Cummings SR et al. N Engl J Med. 1995;332:767-773.
3-4
0-2
Caffeine > 2 Cups Coffee per Day
On Feet ≤ 4 hours per Day
No Walking for Exercise
Can’t Rise From Chair Without
Using Arms
Lowest Quartile Depth Perception
Lowest Quartile Contrast
Sensitivity
Heart Rate > 80
NOF Treatment Guidelines
Initiate therapy to reduce fracture risk in
women with
– 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
†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.
Physician’s Guide to Prevention and Treatment of Osteoporosis. National Osteoporosis Foundation. 2003.
Most Fractures Occur in Patients
with T-score Greater Than -2.5
► 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)
– 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;90:2787-2793. Siris ES et al. Arch Intern Med. 2004;164:1108-1112.
WHO Project
► 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
Fracture Risk Reporting
► 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
► Combination
of clinical risk factors with
BMD may provide a better way of
identifying patients for treatment
Selection of Clinical Risk Factors
► Independent
of BMD (if BMD is known)
► Validated
in multiple populations
(sex, ethnicity, country)
► Easily
obtainable
► Amenable
to intended treatment
► Intuitive
Adapted from Kanis JA et al. Osteoporos Int. 2005;16:581-589.
Clinical Risk Factors
Femoral neck T-score +
► Age
► Previous low trauma fracture
► Current cigarette smoking
► Rheumatoid arthritis
► High alcohol intake (> 2 units/day)
► Parental history of hip fracture
► Prior or current glucocorticoid use
Adapted from Kanis JA et al. Osteoporos Int. 2005;16:581-589.
Intervention Threshold
►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
Decision to Treat
► Fracture
probability
► Cost-effectiveness
► Efficacy
► Safety
► Expected adherence to therapy
► Non-skeletal risks and benefits
► Patient beliefs and preferences
Why do serial BMD testing?
► 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
J Clin Densitom. 2002;5(Suppl):S1-S45.
When should repeat
BMD testing be done?
►
►
When expected change in BMD equals or
exceeds the “Least Significant Change” (LSC)
Intervals between BMD testing should be
determined according to each patient’s 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.
Always Compare BMD
Never Compare T-scores
BMD Values from Different
Manufacturers are Not Comparable
► Different
dual energy methods
► Different
calibration
► Different
detectors
► Different
edge detection software
► Different
regions of interest
Vertebral Fracture Assessment (VFA)
Recognition of vertebral
fracture may
Normal
Vertebral Fx
1.
Change diagnostic
classification
2.
Change estimate of
fracture risk
3.
Change treatment
decisions
Peripheral Measuring Devices
Peripheral Bone Density
Measurement
► Good
prediction of fracture risk
► Good
tool for skeletal health education
► Cannot
be used with the WHO criteria for
diagnosis of osteoporosis
► Not
useful for monitoring bone density
changes
J Clin Densitom. 2002;5(Suppl):S1-S45.
Summary
► 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
► Patients at high risk for fracture are most
likely to benefit from therapy