Comparison Between Calcaneus Quantitative Ultrasound and the Gold Standard DXA in the Ability to Detect Osteoporosis in COPD Patients

Abstract IntroductionOsteoporosis is a prevalent comorbidity in patients with COPD that is usually underrecognized and hence undertreated. Compared to the gold standard dual-energy X-ray absorptiometry (DXA), calcaneus quantitative ultrasound (QUS) is less expensive, more portable, and more accessible, especially in less developed countries. The aim of this study was to investigate the ability of calcaneus QUS to detect osteoporosis in patients with COPD.MethodsThis cross-sectional study enrolled 67 males older than 50 years with clinically stable COPD. DXA scans of the lumbar spine (L2-4) and femoral neck were performed. QUS of the right calcaneus (AOS-100) were used to assess the broadband ultrasound attenuation (BUA), speed of sound (SOS), osteo sono-assessment index (OSI), and T-score. When the T-score was ≤ − 2.5, osteoporosis was diagnosed by both DXA and QUS.ResultsForty-eight patients (71.6%) had DXA T-scores ≤ − 2.5 at either the lumbar spine or femoral neck. All QUS parameters (BUA, SOS, OSI, and T-score) could discriminate DXA-determined osteoporosis (the area under the curve varied from 0.64 to 0.83). The QUS T-score was significantly moderately correlated with the DXA T-score at both the femoral neck (r = 0.62) and lumbar spine (r = 0.53). The sensitivity and specificity of QUS in identifying osteoporosis were 10.4% and 94.7%, respectively. The positive and negative predictive values were 83.3% and 29.5%, respectively.ConclusionThe calcaneus QUS T-score had the ability to identify osteoporosis with an acceptable level of accuracy. However, the sensitivity and specificity of the QUS T-score were not sufficiently high to serve as an alternative diagnostic tool to DXA.