Radiological Assessment and Bone Turnover Markers

Radiological assessment of vertebral fracture

Back pain and loss of height can be the first symptoms of vertebral fractures induced by osteoporosis. In order to assess the severity of vertebral fractures, a semiquantitative method based on visual inspection has been developed. It has been extensively used in clinical trials and epidemiological studies. The severity of the fracture is assessed by measuring the extent of vertebral height reduction, by its morphological changes, and by differentiating the fracture from nonfracture deformities [1].

Grades are assigned to each vertebra based on the degree of height reduction.

This method does not link the type of deformity with the grading of the fracture. One advantage of this method is by assessing the severity of the deformation, new deformities occurring on a prevalent vertebral fracture can be assessed within the range of grading.

Vertebral Fractures Semi-Quantitative Grading
Genant H. et al J Bone Miner Res. 1993; 8:1137-42

Quantitative methods such as morphometry or magnetic resonance imaging (MRI) have been developed over the past years and can be used to assess more precisely the features of vertebral fractures.

Bone Turnover Markers (BTM)

Bone Turnover Markers (BTM) have been extensively used in clinical research to monitor the efficacy and mechanisms of action of new drugs. There are three categories of BTM depending on their origination from the bone mineral unit (BMU): bone resorption markers, bone formation markers and markers of osteoclast regulatory proteins [2].

These markers, measured in serum or urine, are not disease-specific. They assess alterations in skeletal metabolism, regardless of the underlying cause.

Combining BMD with BTM could improve fracture prediction in postmenopausal women [3, 4, 5]. One advantage of biochemical markers compared to BMD is early estimation of treatment effect.

Significant changes in BTM can be seen during antiresorptive therapy after a few weeks of treatment; whereas individual monitoring with DXA usually requires 1-2 years to identify significant changes. As adherence is an important issue of long-term therapy in chronic disease, it has been suggested that BTM could be used in clinical practice to assess the patient's adherence to treatment and also provide feedback on the effectiveness of the medication [6].

See more methods of diagnosing osteoporosis.

References

1. Genant HK, Wu CY, Van Kuijk C, Nevitt MC. Vertebral fracture assessment using a semiquantitative technique. J Bone Miner Res 1993;8:1137-48
2. Leeming DJ, Alexandersen P, Karsdal MA, Qvist P, Schaller S, Tankó LB. An update on biomarkers of bone turnover and their utility in biochemical research and clinical pratice. Eur J Clin Pharmacol 2006 , in press
3. Garnero P. Markers of bone turnover for the prediction of fracture risk. Osteoporos Int. 2000;11 Suppl 6:S55-65
4. Delmas PD, Eastell P, Garnero P, Seibel MJ, Stepan J, Committee of Scientific Advisors of the International Osteoporosis Foundation. The use of biochemical markers of bone turnover in osteoporosis..Osteoporos Int. 2000;11 Suppl 6:S2-17
5. Johnell O, Odén A, De LAet C, Garnero P, Delmas PD, Kanis JA. Biochemical indices of bone turnover and the assessment of fracture probability. Osteoporosis Int 2002;13:523-6
6. Delmas PD, Vrijens B, Roux C, Le-Moigne-Amrani A,. Eastell R, Grauer A, Watts NB, Pols HA, Ringe JD, Cahall D. A Reinforcement Message Based on Bone Turnover Marker Response Influences Long-Term Persistence with Risedronate in Osteoporosis: The IMPACT Study.. ASBMR 2003 [Poster M330]