[Performance of X-ray absorptiometry in post-menopausal vertebral osteoporosis. Discriminant value of vertebral and femoral measurements, fracture threshold, reproducibility].
The aim of this study was to assess the performance of a new bone densitometry technique, X-ray absorptiometry, in vertebral osteoporosis with fracture(s). Vertebral and femoral (neck, Ward's triangle and trochanter) bone density was measured in 60 women with at least one vertebral compression fracture of osteoporotic origin (mean age: 61), 100 controls of the same age and in 40 young adults (mean age: 30). Osteoporosis patients had significantly (p less than 0.0005) low bone density values in comparison with the young adults: -40 to -50% (T-score -1.9 to -2.3) for the femur and with control subjects of the same age: -20 to -30% (Z-score -2.2 to -2.6) for the spine; -10 to -20 (Z-score -1.1 to -1.3) for the femur. Measurements using the spine and Ward's triangle had the best discriminant values assessed by the ROC (Receiver Operating Characteristics) technique (areas under the curve: 95% and 84% respectively). The fracture threshold was fixed at a vertebral bone density of 0.78 g/cm2, this value giving the best compromise between sensitivity (83%) and specificity (95%) with 91% of subjects appropriately classified. Reproducibility was assessed in the short term in 9 osteoporosis patients. The mean standard deviation of measurements was 0.017 g/cm2 (coefficient of variation: 2.6%) as compared with 0.010 g/cm2 (coefficient of variation: 0.8%) in the young adult. These results emphasise the true advance represented by X-ray absorptiometry in the area of bone densitometry, notably in the assessment and monitoring of demineralisation disorders.
Pouillès
J M
JM
Service d'Endocrinologie, Hôpital Purpan, Toulouse.
Trémollières
F
F
Ribot
C
C
D015502:Absorptiometry, Photon / Q000379:methods*; D000328:Adult; D000368:Aged; D015519:Bone Density; D016002:Discriminant Analysis; D005069:Evaluation Studies as Topic; D005260:Female; D005269:Femur; D006801:Humans; D008159:Lumbar Vertebrae; D008875:Middle Aged; D015663:Osteoporosis, Postmenopausal / Q000175:diagnosis*; D015203:Reproducibility of Results; D012307:Risk Factors; D016103:Spinal Fractures / Q000517:prevention & control*
Performances de l'absorptiométrie à rayons X dans l'ostéoporose vertébrale post-ménopausique. Valeur discriminante des mesures vertébrale et fémorale, seuil fracturaire, reproductibilité.