Risk Identification of Osteoporosis in Postmenopausal Women by a Simple Algorithm Based on Ultrasound Densitometry and Body Mass Index

Abstract 

Dual-energy X-ray absorptiometry (DXA) method is the main device for diagnosing osteoporosis; this method, however, involves the use of expensive equipments. Ultrasound method, being portable, noninvasive, and cost-effective, seems to be an appropriate screening device to identify subjects at risk of osteoporosis. Two hundred and twenty-four postmenopausal women (mean age: 57.9±6.2yr) were recruited at 2 Menopause Centers. All subjects were assessed by phalangeal Quantitative Ultrasound (QUS) and by DXA at femur and rachis. Applying the first-level screening strategy, the following risk factors were considered: (1) Amplitude Dependent Speed-of-Sound T-score<−1.8 standard deviation (SD) or Ultrasound Bone Profile Index T-score<−1.8SD; (2) body mass index (BMI)<20kg/m². BMI identified 25 subjects (11%) of the total population as at risk, the QUS parameters 100 subjects (45%), and the combination of the 2 showed 118 subjects (53%). The percentage of osteoporotics identified by BMI was 17%, by QUS 78%, and by the combination of the two 90%. The sensitivity of this algorithm was 90%; 53% of the subjects would undergo a further densitometric evaluation, the remaining 47% were correctly identified as not at risk. The diagnostic work up proposed appears effective to be indicated for extensive clinical employment, thanks also to its simplicity.

Key Words: DXA, osteoporosis, QUS, risk factors