Osteoporosis (2010 Canadian Guidelines)

Rational

Main focus is to reduce fragility fractures.  These types of fractures result in significant morbidity and mortality in the elderly, and they may be preventable.

Epidemiology

Fragility fractures are estimated to represent 80% of all fractures in post-menopausal women over the age of 50.

Fewer than 20% of women and 10% of men are appropriately screened and managed according to current guidelines.

Screening

Targeted to men and women over the age of 50.

Population to screen:

  • Any individual, regardless of age, who has had a fragility fracture
  • All individuals over the age of 65 years
  • Any individual betweein the age of 50-64 years with:
    • fragility fracture over the age of 40
    • prolonged steroid use, defined as at least 3 months in the last year of prednisone >7.5 mg po daily
    • use of other high-risk medications such as aromatase or androgen deprevation therapy
    • Parental hip fracture
    • Vertebral fracture or osteopenia suggested on rediography
    • Current smoker
    • High EtOH intake
    • Low BMD
    • RA
    • Any medical condition associated with OP
  • Individuals <50 years with:
    • Proloned glucocorticoid use
    • Use of high-risk medications
    • Hypogonadism or premature menopause
    • Malabsorption syndrome
    • Primary hyperthyroidism
    • Any disorder strongly associated with bone loss or fracture

Two scoring tools for 10-year fracture risk are currently available (only for individuals >50 years):

Diagnostic Criteria

BMD T-score <-2.5 or a diagnosed fragility fracture is sufficient for the diagnosis of osteoporosis.

Classification

Based on BMD T-scores:

  • 0 to -0.9: normal range
  • -1.0 to -2.4: osteopenia
  • <-2.5: osteoporosis

Risk Factors

Fall risk, undiagnosed vertebral fractures

Physical Exam

Wt (>10% wt loss since age 25 is significant), Ht (change of >6cm from original Ht significant, or >2cm change while montoring), rib-to-pelvis distance should be >2 finger widths, occiput-to-wall distance >5 cm, Get-Up-and-Go test

Investigations

BMD is the screening test of choice.  T value <-2.5 is diagnostic for osteoporosis, <-1.0-2.4 is considered osteopenia

Consider 25-hydroxyvitamin D in select populations after 3 months of supplementation (normal >75 nmol/L), do not measure in healthy adults without any suspicion of low Vitamin D

Ca, ALB, ALP, CBC, Cr, TSH, Serum protein electrophoresis (if vertebral fracture)

Management

Smoking cessation, and exercise focusing of strength, weight-bearing, and balance should be emphasized.  Calcium and vitamin D supplementation is recommended.  High- and moderate-risk individuals should be considered for pharmacologic therapy.  Low risk individuals should be monitored.  Use one of the validated risk-stratifying tools to determine patient risk.

Low risk: may check BMD every 5-10 years.

Moderate risk: Check BMD every 1-3 years.

High risk, started on pharmacologic therapy: check BMD about 1 year after starting therapy to confirm efficacy.

Treatment

Prevention of falls: exercise and home assessment, use of hip-protectors for individuals in long-term care centers that are at high risk of falls

Daily intake of elemental calcium of 1200 mg, along with 1000 IU of vitamin D (400-1000 for low-risk, 800-1000 for mod-risk, can go to 2000 IU, measure after 3 months of supplementation for high risk).  May increase the risk of renal calculi and cardiovascular events.

First line pharmacologic therapy: For women any of alendronate, risedronate, zoledronic acid or denosumab (may increase rates of cellulitis), and for men  alendronate, risedronate or zoledronic acid can be used to reduce the risk of all types of fragility fractures.

Bisphosphonates may cause mild flu-like Sx on first administration in up to 10% of patients.  GI side effects are also common.  Osteonecrosis of the jaw is a suspected rare side-effect (<1 per 10,000 patient years), but it is not clear at this time.  Atypical fractures and esophageal cancer risk are unclear at this time, but may have some association with bisphosphonate use.

In post-menopausal women, raloxifene can be used as first line for vertebral fractures.  If the woman is suffering from vasomotor symptoms as well, HRT can be used to prevent hip, vertebral, and non-vertebral fractures.  Both of these Rx can increase the rate of thromboembolic events, including PE.

Second-line: for post-menopausal women etidronate or calcitonin can be considered to prevent vertebral fractures

All individuals <50 years old who are on a glucocorticoid >7.5 mg po daily for more than 3 months cumulatively in 1 year should be given a bisphosphonate concurrently to prevent bone demineralization.  Without treatment, there is a 30-50% increase in fragility fracture risk in this patient population.

Women talking aromatase inhibitors or androgen-deprivation therapy should be assessed for fracture risk and considered for pharmacologic Rx.

Prognosis

Pharmacologic therapy has been show to reduce the rate of vertebral fractures in women with OP by 30-70%

References

2010 clinical practice guidelines for the diagnosis and management of osteoporosis in Canada: summary. Papaioannou et al.  CMAJ. Oct 12, 2010. http://www.cmaj.ca/content/early/2010/10/12/cmaj.100771.full.pdf.