Transcript Osteoporosis - University of Toronto

Osteoporosis: Review of the
Clinical Practice Guidelines
Ambulatory Internal Medicine Group
Practice Seminar Series
October 2007
Lianne Tile MD MEd FRCPC
References
• Consensus Statement from the
Osteoporosis Society of Canada (OSC) –
CMAJ 2002
• Canadian Task Force on Preventive
Health Care – CMAJ 2004
• Parathyroid hormone for the treatment
of osteoporosis: a systematic review –
CMAJ 2006
Objectives
• At the end of this presentation you will:
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Know the definition of osteoporosis
Understand the recommendations for screening
Have an approach to initial evaluation
Be familiar with nonpharmacological and
pharmacological options for prevention and
treatment
Case
• A 70 year old woman is seen in clinic for
follow-up of refractory hypertension
• She wonders whether she has osteoporosis
• How do you make the diagnosis of
osteoporosis?
• Who should be screened for osteoporosis?
Background
• 1 in 4 Canadian women
• 1 in 8 Canadian men have osteoporosis
• A 50-year-old Caucasian woman has lifetime
fragility fracture risk of at least 40%
• Prevalence of vertebral fractures is >25%
for Canadian women/men > age 50
Osteoporosis - Definition
• A systemic skeletal disease characterized by low
bone mass and micro-architectural
deterioration of bone tissue with resultant
increase in fragility and risk of fracture
• Bone strength depends on bone density and
bone quality
WHO Definition of Osteoporosis
• Based on bone mineral density measured by DEXA (hip
and lumbar spine are preferred sites)
• T-score is the number of standard deviations above or
below the BMD for young adults of the same gender and
race
– Normal BMD: T-score above –1.0
– Osteopenia: T-score between –2.5 and –1.0
– Osteoporosis: T-score below –2.5
– Severe osteoporosis: T-score below –2.5 with a
fragility fracture
– Note: WHO definitions apply to postmenopausal women
• Z-score is age matched
but…what really matters is
osteoporotic fractures
Four key risk factors:
1. Advancing age
2. Prior fragility fracture (after age 40)
3. Family history of osteoporotic fracture
4. Low bone mineral density (BMD)
Why is a history of fracture so
important?
• ↑ risk of future fragility fractures (x1.5–9.5)
• risk of future fractures depends on
– number of prior fractures
– site of initial fracture
– Age
– Fall risk
Who should undergo BMD
testing?
• Each guideline is slightly different
• All recommend testing if
– Age > 65
– Fragility fracture
– Long-term (> 3 months) steroid use
• Osteoporosis Society of Canada recommends
screening in those over 50 with 1 major or 2
minor risk factors (see next slide)
Major and Minor Risk Factors
Major
Minor
Age > 65
Rheumatoid arthritis
Vertebral compression fracture
History of hyperthyroidism
Fragility fracture after age 40
Anticonvulsant therapy
Family history of osteoporsis/ #
Low dietary calcium intake
Steroids > 3 months
Smoking
Malabsorption
Excess caffeine intake
Primary hyperparathyroidism
Weight < 57 kg
Propensity to fall
Weight loss > 10%
Osteopenia on x-ray
Chronic heparin therapy
Hypogonadism
Early menopause (< age 45)
OSC Guideline, 2002
Rational Clinical Exam: Does
this woman have osteoporosis?
• Greatest positive likelihood ratios with:
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Weight <51kg
Tooth count <20
Rib-pelvis distance <2 finger breadths
Wall-occiput distance >0 cm
Self reported humped back
JAMA 2004; 292:2890-2900
Case - Continued
• You review the major and minor risk factors
for osteoporosis, and determine that your
patient has low dietary calcium intake and a
family history of a hip fracture in her mother
• She is also concerned her back in humped
• Based on this, you send her for BMD testing
Case - continued
• What is the diagnosis?
• What additional investigations should be done
at this time?
• Should your patient be treated for osteoporosis,
if so, how?
• What if she was 10 years younger? Taking
corticosteroids?
• This woman has BMD evidence of osteoporosis
• Further assessment should include:
– History:
• Detailed history including diet and lifestyle factors, screen for
risk factors and secondary causes of bone loss
• Past medical history and medications
• Previous fractures, height loss, kyphosis
• Fall risk assessment
– Lab tests for secondary causes of osteoporosis:
• CBC, ALP, calcium, PO4, creatinine in all
• TSH, vitamin D, PTH, serum protein electrophoresis,
testosterone in selected patients
– Spine xrays if exam suggests vertebral fractures
Physical exam: look for changes in the spine
that suggest vertebral fractures
A
B
A. Height Loss > 6 cm
historically or > 2 cm
measured prospectively
B. Wall-Occiput Distance > 0
cm
C. Rib-Pelvis Distance < 2
finger breadths
C
Rational Clinical Exam: Does This Woman Have
Osteoporosis? Amanda D. Green; Cathleen S. ColónEmeric; Lori Bastian; Matthew T. Drake; Kenneth W. Lyles
JAMA 2004; 292: 2890-2900
Case - continued
• No prior fractures as an adult
• History and medications do not suggest a
secondary cause of bone loss
• Mild thoracic kyphosis on examination
• Laboratory investigations reveal a normal
CBC, calcium, ALP, creatinine and SPEP
• Spinal x-rays (done because of kyphosis) show
an old T8 compression fracture
Treatment
• Since her T-score is < -2.5 and she has a
vertebral fracture, you recommend treatment
for her osteoporosis
Start with Nutrition and Lifestyle
(for everyone!)
• Calcium from diet and/or supplements
– Age 19-50: 1,000 mg/day
– Age > 50, steroid use, osteoporosis: 1,500 mg/day
– Note: 1 glass of milk ~ 300 mg calcium
• Vitamin D
– Age < 50: 400 I.U./day
– Age > 50 or low BMD: 800-1000 I.U./day
• Limit caffeine (< 4 cups coffee/day)
• Smoking cessation
• Weight-bearing exercise 3 times per week
When should you consider
pharmacologic therapy?
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Always look at risk of fractures!
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Four Key Risk Factors are:
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Age (and fall risk)
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Prior fragility fracture (after age 40)
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Family history of osteoporotic fracture
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Low bone mineral density (BMD)
Canadian Guidelines Recommend
Pharmacological Options
• Antiresorptive agents
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Bisphosphonates
Selective estrogen receptor modulators
Hormone replacement therapy
Calcitonin
IV Bisphosphonates
• Bone formation agents
– PTH
• Choose based on efficacy, safety, toxicity
Alendronate (Fosamax) /
Risedronate (Actonel)
– good quality studies show decreases in risk of spine and
nonvertebral fractures
– Evidence for effectiveness in women and men
– Taken weekly, on an empty stomach, 1 hour before
eating, must remain upright
– Adverse effects: GERD or esophageal erosions, use with
caution in renal insufficiency, osteonecrosis of the jaw is
a very rare association
– recommended as first line therapy, covered by ODB
Etidronate (Didrocal)
– shown to prevent spine but not hip fractures
– taken cyclically: 400 mg/d x 14 days q 3 mo as
Didrocal “kit”: 14 tablets of etidronate followed
by 10 weeks of calcium 500 mg
– Well tolerated
– recommended as second line therapy
SERMs: Raloxifene (Evista)
– Estrogen agonist effect on bone, heart;
antagonist on breast; neutral on endometrium
– Decreases risk of invasive breast cancer, neutral
for cardiovascular disease
– Studies show decreased risk of vertebral but not
hip fractures
– Taken daily
– Adverse effects include hot flushes, increased
risk of thromboembolic disease (similar to
HRT)
– covered by ODB under limited use criteria
Hormone Replacement
Therapy (HRT)
• Good quality data (Women’s Health Initiative)
showing decreased risk of fractures at all sites
• BUT increased risk of coronary artery disease,
stroke, venous thromboembolism and breast
cancer
• Although HRT is effective therapy for prevention
and treatment of osteoporosis, risks will outweigh
benefits for most women
Calcitonin
• Intranasal calcitonin (Miacalcin)
– fair quality data showing decreased risk of
fractures
– Reduces pain in acute vertebral fractures
– well tolerated, safe in renal failure, mild nasal
irritation in 30%
– recommended as second-line therapy
– not covered by ODB
Bone Formation Agents
• PTH 1-34 (Forteo)
– Significantly increases bone density, decreases risk of
vertebral and nonvertebral fractures
– Daily sc injection for 18 months (self administered)
– Less effective if given with a bisphosphonate
– Tumors seen in animal studies, so PTH is not
recommended in high bone turnover states or in cancer
patients
– Very expensive, not covered
New Treatment Options
• IV Bisphosphonates
– IV Zoledronic acid 5 mg given once a year reduces
fracture risk similar to oral bisphosphonates
– There is further evidence that it decreases mortality
when given post hip fracture
– Not yet approved in Canada for osteoporosis treatment
• Vertebroplasty
– Injection of bone cement into vertebral fracture for pain
relief (done by interventional radiologist)
• New therapies on the horizon
– Strontium ranelate
– RANK ligand inhibitors
Back to the Case
• You recommend calcium 500 mg (elemental) TID,
vitamin D 1000 IU daily, and weight bearing
exercise
• You offer treatment with alendronate, risedronate
or raloxifene, and discuss the benefits and side
effects of each
• She agrees to start alendronate 70 mg per week
and understands how to use it correctly
• You arrange a follow up BMD in 1-2 years’ time