Bone Fracture Index With Bone Mineral Density

Bone fracture risk factors

The above fracture index accounts for the BMD-T result along with other patient parameters which are involved in increasing the risk of fracture:

The bone fracture index with bone mineral density provides an immediate result. Patients older than 65 are at higher risk of developing osteoporosis and suffer from a fracture. In the BMD-T, the lower the test result, the higher the fracture risk.

If the patient requires arm assistance when standing from a chair, this is an indication of poor stability and a two-fold increased risk of fracture of people with a BMI of 20 compared to those with a BMI of 25. Patients with body weight less than 125 lbs are labelled as frail.

Personal history of fractures increases risk whilst smoking is recognized as a bone thinning factor.

There are several other osteoporosis and fracture risk factors such as the coexistence of rheumatoid arthritis, treatment with glucocorticoids, vitamin D and calcium deficit nutrition.

Trauma risk is increased in patients who experience frequent falls due to loss of balance, visual impairment or dementia.

Gait speed or the actual mechanism of trauma can also contribute to higher or lower risks, for example, falling to the side increases hip fracture risk by 6 times.

Result interpretation

Each of the 7 items in the above fracture index are weighted differently, according to their impact as risk factors and their involvement in weakening bone density.

The result obtained by summing the number of points awarded is interpreted according to the following table:

About the study

The above form is based on the Fracture Index developed by Black et al. in 2001 following a study based on data from the Study of Osteoporotic Fractures (SOF).

This included a total of 7782 women aged 65 years and older with bone mineral density (BMD) measurements and baseline risk factors.

The index was found to be predictive of three types of fractures hip, nonvertebral and vertebral and was validated using the EPIDOS fracture study. It was also found that the index can be used with or without the BMD testing if that is not available.

This risk prediction can contribute to the reduction of morbidity and mortality associated with untreated osteoporosis in high risk individuals.

BMD T explained

The bone mineral density test is designed to compare the subject’s body density value with those from the normal range (obtained by healthy adults of the same age).

The T-score is given as units, which is the standard deviation by which the subject’s test result is above or below the average.

The following table introduces the three categories of results:

There is an alternative version of the test, the Z-score, which account for age, gender, weight and ethnicity of the patient.

The radiation involved in a bone mineral density test is less than that in chest x-rays. This analyses bones that are likely to undergo a fracture, such as lumbar vertebrae, femoral neck or forearm bone.

Not all cases of low bone mass are indicative of osteoporosis. Usually in osteoporosis low bone mass is accompanied by other risk factors, as explained above, along with bone affecting comorbidities or accelerated bone loss.

There are several types of patients (aside from females over 65 and males over 70) who are recommended regular testing:

■ Patients over 50 with personal history of bone fracture from minor trauma, rheumatoid arthritis or with parental history of hip fracture;

■ Patients with vertebral anomalies;

■ Patients diagnosed with hyper parathyroidism.

Original source

Black DM, Steinbuch M, Palermo L, Dargent-Molina P, Lindsay R, Hoseyni MS, Johnell O. An assessment tool for predicting fracture risk in postmenopausal women. Osteoporos Int. 2001; 12(7):519-28.

Other references

1. Unnanuntana A, Gladnick BP, Donnelly E, Lane JM. The Assessment of Fracture Risk. J Bone Joint Surg Am. 2010; 92(3): 743–753.

2. Lewiecki EM. Bone density measurement and assessment of fracture risk. Clin Obstet Gynecol. 2013; 56(4):667-76.