26th January 2024

Calculating fracture risk 

The diagnosis of osteoporosis is mainly based on an assessment of BMD. However, most osteoporotic fractures occur in patients who do not have a T score of less than -2.5; therefore, an assessment of clinical risk factors and the extent to which these can contribute towards risk of fall should be carried out, independently of BMD. According to NICE guidelines, patients who are at high risk of developing osteoporosis should have an assessment of fracture risk prior to arranging a DEXA scan – this can be done by using a validated online risk calculator such as QFracture or FRAX, which predict the absolute risk of hip and major osteoporotic fracture over a 10 year period. The FRAX calculator calculates the probability of people between the ages of 40 and 90 having a major fragility fracture. The following risk factors are taken into account:

• Sex
• BMI
• History of previous fracture
• Parental history of fracture
• Current smoking status
• Use of glucocorticoids
• History of rheumatoid arthritis
• Secondary osteoporosis
• Alcohol intake of 3 or more units per day
• Femoral neck BMD (if result available)

Patients are then classified as being low, intermediate or high risk according to their results, and subsequent NOGG advice is given regarding the need for treatment. The QFracture score is based on UK data and can be calculated for patients aged 30-99 without a value for BMD. In addition to the risk factors calculated in the FRAX score, the QFracture score also includes ethnicity, residence in care home, history of falls, dementia, cerebrovascular disease, chronic liver disease, and whether the patient is on high-risk medications other than glucocorticoids. Those patients who are identified as having a 10-year fracture risk of 10% or more should then be considered for undergoing a DEXA scan. Fragility fracture risk scores should ideally be carried out prior to DEXA scan; however, in patients over the age of 50 years with a history of fragility fracture or patients younger than 40 years with major risk factors for fracture, DEXA can be carried out without the use of FRAX or QFracture scores.