Peripheral bone densitometry.

I. Peripheral densitometry systems

A. Peripheral systems are portable, stand-alone devices that measure attenuation of x-ray or ultrasound energy that is passed through bone. (1)

B. Overview of technology: there is great diversity in system design and operation. (1)

II. Clinical application

A. What is the evidence that peripheral systems detect osteoporosis and predict fractures?

1. Despite the fact that all the early work in the field was done using peripheral (mainly forearm) systems, (2-5) the role of peripheral densitometry in the diagnosis and management of osteoporosis is controversial.

2. Facts:

a. Output variables of peripheral systems are generally correlated with bone strength and BMD by central DXA. (6,7)

b. Peripheral systems can differentiate osteoporotic patients (with and without preexisting fractures) from normals. (8-10)

c. Peripheral systems can predict global fracture risk in postmenopausal women nearly as well as central DXA. (11-14)

B. Reality check: controlled clinical trials versus realworld use of peripherals.

1. Technical limitations affect utility.

a. Ambient temperature, edema, foot size, injuries, etc. may confound measurements. (15-17)

b. Output variables differ among peripheral systems.

c. Regions of interest differ among peripheral systems. (15,18-20)

d. Normative databases differ among peripheral systems. (20)

e. Diagnostic discrepancy exists among peripheral systems. (20)

f. Operation: generally no in-person, manufacturer-guided training.

2. T-scores from peripherals can be used to assess fracture risk but should not be used to make a diagnosis following World Health Organization criteria. (21-23)

a. T-score cutpoints vary among peripheral systems. (19-21)

b. Sensitivity and specificity of peripheral systems compared with central DXA for detecting osteopenia and osteoporosis generally does not meet International Society for Clinical Densitometry recommendations. (21,24-26)

c. Discordance with central DXA. (21,27)

3. Results of most (but not all) studies suggest that peripherals should not be used to monitor patients on antiresorptive treatment. (21)

4. Use with men and premenopausal women is commonplace but not well validated.

5. Lack of interpretation guidelines leads to confusion about what to do with results (eg, when should additional testing with central DXA be recommended?). (28,29)

6. Reporting of results is often poorly done, especially in nonmedical settings.

7. Educational and wellness programs are good venues for use of peripheral systems. (30)

The following references are examples representative of the published literature. This list is not meant to be comprehensive.

Accepted March 15, 2004.

Copyright [c] 2004 by The Southern Medical Association

0038-4348/04/9706-0542

References

1. Bonnick SL and Lewis LA. 2002 Densitometry Devices Approved by the Food and Drug Administration, in Bone Densitometry for Technologists. Totowa, New Jersey, Humana Press, 2002, pp 99-144.

2. Cummings SR, Black DM, Nevitt MC, et al. Appendicular bone density and age predict hip fracture in women. The Study of Osteoporotic Fractures Research Group. JAMA 1990;263:665-668.

3. Hui SL, Slemenda CW, Johnston CC. Baseline measurement of bone mass predicts fracture in white women. Ann Int Med 1989;111:355-361.

4. Gardsell P, Johnell O, Nilsson BE. The predictive value of bone loss for fragility fractures in women: a longitudinal study over 15 years. Calcif Tissue Int 1991;49:90-94.

5. Black DM, Cummings SR, Melton LJ. Appendicular bone mineral and a woman's lifetime risk of hip fracture. J Bone Mineral Res 1992;7(6):630-646.

6. Bouxsein ML, Radloff SE. Quantitative ultrasound of the calcaneous reflects the mechanical properties of calcaneal trabecular bone. J Bone Miner Res 1997;12(5):839-846.

7. Lee SC, Coan BS, Bouxsein ML. Tibial ultrasound velocity measured in situ predicts the material properties of tibial cortical bone. Bone 1997;21(1):119-125.

8. Greenspan SL, Bouxsein ML, Melton ME et al. Precision and discriminatory ability of calcaneal bone assessment technologies. J Bone Miner Res 1997;12(8):1303-1313.

9. Turner Ch, Peacock M, Timmerman L, et al. Calcaneal QUS measurements discriminate hip fracture independently of bone mass. Osteoporosis Int 1995;5:130-135.

10. Schott AM, Weill-Engerer S, Hans D, et al. QUS discriminates patients with hip fracture equally well as dual-energy x-ray absorptiometry and independently of bone mineral density. J Bone Mineral Res 1995;10:243-209.

11. Marshall D, Johnell O, Wedel H. Meta-analysis of how well measures of bone mineral density predict occurrence of osteoporotic fractures. BMJ 1996;312:1254-1259.

12. Thompson P, Taylor J, Fisher A, et al. Quantitative heel ultrasound in 3180 women between the 45 and 75 years of age: compliance, normal ranges and relationship to fracture history. Osteoporosis Int 1998;8:211-214.

13. Hans D, Dargent-Molina P, Schott AM, et al. Ultrasonic heel measurements to predict hip fracture in elderly women: the EPIDOS prospective study. Lancet 1996;348:511-514.

14. Bauer DC, Gluer CG, Cauley JA, et al. Broadband ultrasound attenuation predicts fractures strongly and independently of densitometry in older women. Arch Int Med 1997;157:629-634.

15. Cheng S, Njeh CF, Fan B, et al. Influence of region of interest and bone size on calcaneal BMD: implications for the accuracy of quantitative ultrasound assessments at the calcaneus. Br J Rad 2002;75:59-68.

16. Johansen A, Stone MD. The effect of ankle oedema on bone ultrasound assessment at the heel. Osteoporosis Int 1997;7:44-47.

17. Iki M, Kajita E, Mitamura S, et al. Precision of quantitative ultrasound and effects of ambient temperature on the parameters. Osteoporosis Int 1999;10(6):462-467.

18. Kang C. Speller R. Comparison of ultrasound and dual x-ray absorptiometry measurements in the calcaneus. Br J Rad 1998;71:861-867.

19. Shepherd JA, Cheng XG, Lu Y, et al. Universal standardization of forearm bone densitometry. J Bone and Mineral Res 2002;17(4):734-745.

20. Njeh CF, Hans D, Li J, et al. 2000 Comparison of six calcaneal quantitative ultrasound devices: precision and hip fracture discrimination. Osteoporosis Int 11(12):1051-1062.

21. Miller PD, Njeh CF, Jankowski LG, et al. 2002 International Society for Clinical Densitometry Position Development Panel and Scientific Advisory Committee. What are the standards by which bone mass measurement at peripheral skeletal sites should be used in the diagnosis of osteoporosis? J Clin Densitometry. 5 Suppl:S39-S45.

22. Siris ES, Miller PD, Barrett-Connor E, et al. Identification and fracture outcomes of undiagnosed low bone mineral density in postmenopausal women: results from the National Osteoporosis Risk Assessment. JAMA 2001;286(22):2815-2822.

23. Kanis JA, Gluer CC. An update on the diagnosis and assessment of osteoporosis with densitometry. Committee of Scientific Advisors, International Osteoporosis Foundation. Osteoporosis Int 2000;11(3):192-202.

24. Bachman M, Crewson PE, Lewis RS. Comparison of heel ultrasound and finger DXA to central DXA in the detection of osteoporosis. J Clin Densitometry 2002;5(2):131-141.

25. Pearson D, Masud T, Sahota O, et al. A comparison of calcaneal dual-energy x-ray absorptiometry and calcaneal ultrasound for predicting the diagnosis of osteoporosis from hip and spine densitometry. J Clin Densitometry 2003;6(4):345-351.

26. Jorgensen HL, Warming L, Bjarnason NH, et al. How does quantitative ultrasound compare to dual x-ray absorptiometry at various skeletal sites in relation to the WHO diagnosis categories? Clin Phys 2001;21(1):51-59.

27. Faulkner KG, von Stetten E, Miller PD. Discordance in patient classification using T-scores. J Clin Densitometry 1999;2(3):343-350.

28. Miller PD, Bonnick SL, Johnston CC, et al. The challenges of peripheral testing: which patients need additional central density skeletal measurements? J Clin Densitometry 1998;1(3):211-217.

29. Baran DT, Faulkner KG, Genant HK, et al. Diagnosis and management of osteoporosis: guidelines for the utilization of bone densitometry. Calcif Tissue Int 1997;61(6):433-440.

30. Elliott ME, Meek PD, Kanous NL, et al. Osteoporosis screening by community pharmacists: use of National Osteoporosis Foundation resources. J Am Pharm Assoc (Wash) 2002;42(1):101-110.

Gary M. Kiebzak, PHD

Center for Orthopaedic Research and Education, St. Luke's Episcopal Hospital, Houston, TX.

Presented at the Southern Medical Association's 7th Conference on Osteoporosis, Sea Island, GA, February 19-22, 2004.

Reprint requests to Gary M. Kiebzak, Center for Orthopaedic Research and Education, St. Luke's Episcopal Hospital, 6720 Bertner Avenue, Houston, TX 77030.