Discordance Between Hip and Spine Bone Mineral Density Measurement Using DXA: Prevalence and Risk Factors

• Published in: Seminars in arthritis and rheumatism Vol. 38; no. 6; pp. 467 - 471
• Main Authors: Mounach, A., MD, Mouinga Abayi, D.A., MD, Ghazi, M., MD, Ghozlani, I., MD, Nouijai, A., MD, Achemlal, L., MD, Bezza, A., MD, El Maghraoui, A., MD
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01.06.2009; Elsevier
• Subjects: Absorptiometry, Photon - methods; Adult; Aged; Aged, 80 and over; Biological and medical sciences; Bone Density - physiology; bone mineral density; concordance; Diagnostic Errors - statistics & numerical data; Diseases of the osteoarticular system; dual energy x-ray absorptiometry (DXA); Female; Femur - diagnostic imaging; Femur - metabolism; Humans; Investigative techniques, diagnostic techniques (general aspects); Logistic Models; Lumbar Vertebrae - diagnostic imaging; Lumbar Vertebrae - metabolism; Male; Medical sciences; Menopause; Middle Aged; Multivariate Analysis; Osteoarticular system. Muscles; osteoporosis; Osteoporosis - diagnosis; Osteoporosis - diagnostic imaging; Osteoporosis - metabolism; Osteoporosis. Osteomalacia. Paget disease; Radiodiagnosis. Nmr imagery. Nmr spectrometry; Reproducibility of Results; Rheumatology; Risk Factors; Young Adult; bone mineral density; osteoporosis; dual energy x-ray absorptiometry (DXA); concordance; Prevalence; Spine; Diseases of the osteoarticular system; Discordance; Hip bone; Rheumatology; Epidemiology; Hip; Osteoporosis; X ray absorption spectrometry; Dual energy absorptiometry; Risk factor; Bone mineral density
• ISSN: 0049-0172; 1532-866X
• DOI: 10.1016/j.semarthrit.2008.04.001

Background Diagnostic discordance for osteoporosis is the presence of different categories of T-scores in 2 skeletal sites of an individual patient, falling into 2 different diagnostic categories identified by the World Health Organization classification system. Objectives To evaluate the prevalence and risk factors for T-score discordance between spine and total hip measurement sites. Methods Demographic data, anthropometric measurements, and risk factors for osteoporosis were derived from a database of 3479 patients referred to a community-based outpatient osteoporosis testing center. Dual-energy x-ray absorptiometry (DXA) was performed on L1-L4 lumbar spine and total hips for all cases. Minor discordance was defined as present when the difference between 2 sites was no more than 1 World Health Organization diagnostic class. Major discordance was present when 1 site is osteoporotic and the other is normal. Subjects with incomplete data were excluded. Results In 3479 participants (2871 women; mean age, 55.7 ± 11.9 years), concordance of T-scores, minor discordance, and major discordance were seen in 54, 42, and 4%, respectively. In multivariate logistic regression analysis, age, menopause, and obesity were identified as risk factors against T-score discordance. Conclusion Densitometrists and clinicians should expect that at least 4 of every 10 patients tested by DXA to demonstrate T-score discordance between spine and total hip measurement sites. T-score discordance can occur for a variety of reasons related to physiologic and pathologic patient factors as well as the performance or analysis of DXA itself.