UHN/MSH Medical Consult Service
Endocrinology -
Osteoporosis
Background:

  • We see many patients on the consult service who have been admitted with a hip
    fracture or other low trauma fracture.
  • The presence of a low trauma fracture in the elderly strongly suggests the diagnosis
    of osteoporosis, although malignancy and metabolic causes need to be ruled out.
  • Once these are ruled out, osteoporosis can be diagnosed and treatment started
    irrespective of the bone mineral density.
  • A low trauma fracture increases the risk of a future fracture by 1.5-9.5%.  Those with
    a hip fracture have an especially high rate of a second hip fracture (above 20%).
  • There are effective treatments for secondary prevention of fractures in this high-risk
    population.  Even though we are usually consulted for a different reason, it is
    important that the osteoporosis be addressed.
Workup:

  • History to look for any medications that may contribute to bone loss – Steroids,
    heparin, antiseizure medication, androgen and estrogen deprivation therapies,
    more recent evidence for PPIs, SSRIs, rosiglitazone
  • Screening labs to rule out secondary causes of bone loss:  Calcium, creatinine,
    ALP (although this is often high after fractures), liver enzymes, TSH, serum
    protein electrophoresis.  PTH and vitamin D levels are useful in specific situations.
  • Pathologic fracture secondary to malignancy must be ruled out – this requires
    different treatment.
Management:

  • Start elemental calcium 500 mg daily, increased to two or three times a day as
    tolerated, or less depending on dairy intake.  
  • Start Vitamin D 1000 IU per day.
  • Consider oral bisphosphonate therapy
  • Alendronate 70 mg per week and Risedronate 35 mg per week have strong
    evidence for reduction in vertebral and nonvertebral fracture risk.  
  • Cautions – risk of esophagitits and GI intolerance, so they must be taken on
    an empty stomach, in the upright position with a large glass of water, 1 hour
    prior to taking food or medications.  
  • This is difficult to achieve in hospital, so it is often necessary to start
    bisphosphonates in rehab or at home.  There is a printable form of the
    consults website that you can give to patients so they can follow up with their
    family MD.
  • If a patient is ambulatory and willing, a bone density study should be done as a
    baseline, and so it can be followed to assess response to treatment.  In less mobile
    patients with a hip fracture, bisphosphonates can be used even if a bone density
    study can not be done
  • Patients can also be referred to the UHN osteoporosis program, 416-340-3890.
Future directions:
  • There is recent evidence that IV zoledronic acid (Aclasta) 5 mg given once a
    year, as compared to placebo, is similarly effective to oral bishosphonates in
    reducing fractures, and in patients who have had a hip fracture it has been shown
    to reduce mortality.  It is not yet widely available to treat osteoporosis, but when it
    is it will be a useful option for treating osteoporosis.
Osteoporosis management in the orthopedic patient

By: Lianne Tile
References:

  • Lyles KW, et al: Zoledronic Acid and Clinical Fractures and Mortality after Hip
    Fractures.  NEJM Nov 2007. 357;18: 1799-1809