The Optimal Cut-Points for Weight and Non-Weight Quantitative Ultrasound of the Calcaneus to Screen Osteoporosis in Postmenopausal Women.

Objective: To determine the optimal cut-off point of quantitative ultrasound (QUS) of the calcaneus, and optimized position for QUS of the calcaneus, between non-weight (sitting) and weight (standing) position, to screen osteoporosis in postmenopausal women.

Material And Method: A cross-sectional study of postmenopausal women aged 65 years or older who came for bone mineral density (BMD) evaluation at the menopause unit, Department of Obstetrics and Gynecology, Ramathibodi Hospital between April 2013 and October 2015. Bone tissue was measured by using QUS of the calcaneus in the standard sitting (non-weight position) and in standing (weight position) consecutively of non-dominant calcaneus to compared with BMD that measured by dual energy X-ray absorptiometry (DXA) of lumbar spine and hip within the same visit of QUS measurement. The area under Receiver Operating Characteristic (ROC) curve and optimal of diagnostic properties to diagnosed osteoporosis were analyzed by sensitivity, specificity, positive and negative likelihood ratio (LR +/-).

Results: One hundred sixty one postmenopausal women were enrolled, median age was 70 (65, 94) years old, median time since menopause was 22 (10, 55) years. Ten point five percent of subjects had history of osteoporotic fracture at wrist. The prevalence of osteoporosis was 23% at lumbar spine and 30% at femoral neck respectively. Area under ROC curve for diagnosed osteoporosis was 0.73 in the non-weight QUS of the calcaneus and correlated well with using DXA at neck of femur (gold standard). However the weight or standing position did not improve the diagnostic power of QUS of the calcaneus. The optimal cut-point value of QUS of the calcaneus to screen osteoporosis at stiffness index was determined by T-score of ≤ -2.6 with 81.42%, 45.83%, 1.5, and 0.41 for the sensitivity, specificity, LR +/- respectively.

Conclusion: QUS of the calcaneus was acceptable and promising to be alternative tool for screening osteoporosis in postmenopausal woman age older than 65 years by the optimal cut-point of stiffness index T-score at ≤ -2.6 measured in standard position or non-weight method.