Combined clinical risk indices with quantitative ultrasound calcaneus measurement for identifying osteoporosis in Thai postmenopausal women.

OBJECTIVE To examine the diagnostic performance of clinical risk indices combined with quantitative ultrasound calcaneus measurement (QUS) for identifying osteoporosis in Thai postmenopausal women. MATERIAL AND METHOD The present study was designed as a cross-sectional investigation in 300 Thai women, aged between 38 and 85 years (mean age: 58). Femoral neck bone mineral density (BMD) was measured by DXA (Hologic QDR-4500; Hologic, Bedford, MA, USA). A BMD T-scores < or = -2.5 was defined as "osteoporosis"; otherwise, "non-osteoporosis". QUS was measured by Achilles+ (GE Lunar, Madison, WI, USA) and converted to T-score. The OSTA and KKOS score was calculated for each woman using her age and weight Women with OSTA/KKOS scores < or = -1 and > -1 were classified as "high risk" and "low risk", respectively. RESULTS Using DXA as the gold standard, the sensitivity of QUS to identify osteoporosis was lower than the sensitivity of OSTA/KKOS (60 vs. 71/74%) but the specificity and PPV of QUS were higher than OSTA/KKOS. The sensitivity increased when using OSTA/KKOS combined with QUS to identify osteoporosis (approximately 87-89%) while the specificity, PPV and NPV were comparable with using clinical risk indices alone. The risk (odds ratio; OR) of osteoporosis when QUS T-score < or = -2.5 alone was 9.94 (95%CI: 4.74-20.87), which was higher than high risk by OSTA/KKOS alone (OR: 6.35, 95%CI: 2.99-13.47 for OSTA and 8.15, 95%CI: 3.76-17.66 for KKOS). Furthermore, individuals were classified "high risk" from OSTA/KKOS with QUS T-score < or = -2.5SD, the risk of osteoporosis was increased (OR: 43.68, 95%CI: 13.89-137.36 and OR: 60.92, 95%CI: 17.69-209.76 for OSTA and KKOS, respectively). CONCLUSION Using the clinical risk indices combined with QUS could improve the accuracy of osteoporosis identification. This approach could be used in a primary care setting or community-based hospital where a DXA machine is not available.