2010 clinical practice guidelines for the diagnosis and management of osteoporosis
in Canada: summary
Since the publication of the Osteoporosis Canada guidelines in 2002, there has been a paradigm shift in the prevention and treatment of osteoporosis and fractures.1,2 The focus now is on preventing fragility fractures and their negative consequences, rather than on treating low bone mineral density, which is viewed as only one of several risk factors for fracture. Given that certain clinical factors increase the risk of fracture independent of bone mineral density, it is important to take an integrated approach and to base treatment decisions on the absolute risk of fracture. Current data suggest that many patients with fractures do not undergo appropriate assessment or treatment.3 To address this care gap for high-risk patients, the 2010 guidelines concentrate on the assessment and management of women and men over age 50 who are at high risk of fragility fractures and the integration of new tools for assessing the 10-year risk of fracture into overall management.
Burden and care gaps Fragility fractures, the consequence of osteoporosis, are responsible for excess mortality, morbidity, chronic pain, admission to institutions and economic costs.4-6 They represent 80% of all fractures in menopausal women over age 50.3 Those with hip or vertebral fractures have substantially increased risk of death after the fracture.5 Postfracture mortality and institutionalization rates are higher for men than for women.
Despite the high prevalence of fragility fractures in the Canadian population and the knowledge that fractures predict future fractures,8 fewer than 20% of women3,9 and 10% of men10 receive therapies to prevent further fractures. These statistics contrast sharply with the situation for cardiovascular disease, where 75% of patients who have had myocardial infarction receive β-blockers to prevent another event.
Scope of the guidelines
The target population for these guidelines is women and men over age 50, because of the overall burden of illness in that age group. As a consequence, we focused our systematic literature reviews on this population. The application of these guidelines to children and young adults, as well as high-risk groups such as transplant recipients, was considered, but indepth reviews of conditions that increase risk were largely beyond the scope of these guidelines.
Clinical recommendations
Who should I assess for osteoporosis and fracture risk?
Women and men over age 50 should be assessed for risk factors for osteoporosis and fracture to identify those at high risk for fractures.
1. Individuals over age 50 who have experienced a fragility fracture should be assessed [grade A].
How do I assess for osteoporosis and fracture risk?
A detailed history and a focused physical examination are recommended to identify risk factors for low bone mineral density, falls and fractures, as well as undiagnosed vertebral fractures (Appendix 1, available at www.cmaj.ca/cgi/content/full /cmaj.100771/DC1). In selected individuals, bone mineral density should be measured with dual-energy x-ray absorptiometry (Table 1).
1. Measure height annually, and assess for the presence of vertebral fractures [grade A].
2. Assess history of falls in the past year. If there has been such a fall, a multifactorial risk assessment should be con-ducted, including the ability to get out of a chair without using arms [grade A].
What investigations should I order initially?
For most patients with osteoporosis, defined as bone mineral density of 2.5 or more standard deviations below the peakbone mass for young adults (i.e., T-score ≤ -2.5), only limited laboratory investigations are usually required (Box 1). Increased values for bone turnover markers are associated with an approximately two-fold increased risk of fractures,which is largely independent of bone mineral density; however the value of measuring these markers to estimate an individual's risk of fracture is unclear.
1. Perform additional biochemical testing to rule out secondary causes of osteoporosis in selected patients, on the basis of the clinical assessment [grade D].
2. Measure serum level of 25-hydroxyvitamin D in individuals who will receive pharmacologic therapy for osteoporosis, those who have sustained recurrent fractures or have bone loss despite osteoporosis treatment, and those with comorbid conditions that affect absorption or action of vitamin D [grade D].
3. Serum 25-hydroxyvitamin D should be measured after three to four months of adequate supplementation and should not be repeated if an optimal level (≥ 75 nmol/L) is achieved [grade B].
4. Serum 25-hydroxyvitamin D should not be measured in healthy adults at low risk of vitamin D deficiency, i.e.,without osteoporosis or conditions affecting the absorption or action of vitamin D [grade D].
Assessment for vertebral fractures by dual-energy x-ray absorptiometry is available as an option on some bone densitometers.16 Vertebral fractures unrelated to trauma are best defined (on lateral radiographs or via vertebral fracture assessment) as vertebral height loss of 25% or more with disruption of the end plate. Such fractures are associated with a five-fold increase in the risk of future vertebral fractures relative to those without vertebral fractures.17
1. Perform lateral thoracic and lumbar spine radiography or vertebral fracture assessment by dual-energy x-ray absorp tiometry if clinical evidence is suggestive of a vertebral fracture [grade A].
How do I assess 10-year fracture risk?
Currently, two closely related tools are available in Canada for estimating the 10-year risk of a major osteoporotic fracture(i.e., fracture of the hip, vertebra [clinical], forearm or proximal humerus): the updated tool of the Canadian Association of Radiologists and Osteoporosis Canada (CAROC; see www.osteoporosis.ca)18 and the Fracture Risk Assessment tool (FRAX) of the World Health Organization (WHO), specific for Canada www.sheffield.ac.uk/FRAX/tool.jsp?country=19).19 Both use the bone mineral density or T-score for the femoraneck only. They have been calibrated using the same Canadian fracture data and have been directly validated in Canadians.20-22 The 2010 version of the Canadian Association of Radiologists and Osteoporosis Canada tool replaces the 2005 version, which used Swedish fracture data.23
