Fracture risk—beyond BMD

In addition to building healthy bones, preventing fractures is one of the keys to managing osteoporosis.1 It is now clear that fracture risk reduction correlates with many factors, not just BMD. In other words, larger increases in BMD, do not necessarily correlate to greater reduction in fracture risk.2

Assessing fracture risk
 
When assessing a patient’s risk of minimal trauma fracture (MTF), the many factors that contribute to the risk need to be considered (Table). Keep in mind that having one major risk factor (eg, low BMD) does not necessarily predict overall fracture risk.1

Fracture risk calculators can help identify the degree of risk for individual patients. Among these, the Garvan Institute’s Fracture Risk Calculator and WHO’s FRAX are quick and easy to use, incorporating clinical risk factors to calculate fracture risk at 5 and 10 years (Garvan) and at 10 years (FRAX).3

FRAX includes more parameters than the Garvan tool. However it does not use cumulative fracture and falls history. These highly relevant parameters are used in the Garvan calculator.3 In a longitudinal Norwegian study designed to validate this calculator in more than 3000 men and women over the age of 60, incident MTFs were recorded over a 10-year period. Actual fracture incidence was compared with risk of fracture at 5 and 10 years, with close agreement being found between predicted and observed risk in men and women at all levels of risk apart from the highest predicted risk. At this level, the Garvan calculator overestimated 5- and 10-year fracture risk.4

You can access the Garvan calculator at: www.garvan.org.au/bone-fracture-risk.

FRAX can be found at: www.shef.ac.uk/FRAX/tool.jsp

Note that these risk calculators are still being developed and should only be used as a guide to management.3

Table. Risk factors for osteoporotic fracture.1
 
Modifiable Advanced age (>65 years)
Low BMD Advanced age (>65 years)
Low body weight Female gender
Oral glucocorticoid therapy Early menopause (<45 years)
Increased risk of falls Amenorrhea (>6-12 months)
Cigarette smoking Primary hypogonadism
Regular excessive alcohol intake Previous MTF
Sedentary lifestyle Family history of MTF
Inadequate calcium intake Slim build
Vitamin D deficiency Asian or Caucasian race
Vitamin D deficiency  
Other secondary causes of osteoporosis (eg, rheumatoid arthritis, etc)  

1. NPS MedicineWise News. (Accessed March 10, 2016, at www.tinyurl.com/h4etryy).
2. Divittorio G, et al. Pharmacotherapy 2006;26:104-14.
3. Croucher LC. Osteoblast 2015;Summer:1-8.
4. Ahmed LA, et al. PLoS One 2014;9:e107695.