Comparison of the Osteoporosis Self-Assessment Tool for Asians and the fracture risk assessment tool - FRAX to identify densitometric defined osteoporosis: A discriminatory value analysis in a multi-ethnic female population in Southeast Asia

• Main Authors: Manju Chandran, Yun Ann Chin, Kuan Swen Choo, Wan Chen Ang, Xiao Feng Huang, Xiao Ming Liu, Donovan Tay, Tin Kyaw Kyaw Aung, Amin Ali, Win Pa Pa Thu, Susan Logan, Sean Xuexian Yan, Sarath Lekamwasam, Ying Hao
• Format: Article
• Language: English
• Published: Elsevier 2020-06-01
• Series: Osteoporosis and Sarcopenia
• Subjects: Asia; Assessment threshold; FRAX; OSTA; Osteoporosis; Screening
• Online Access: http://www.sciencedirect.com/science/article/pii/S2405525520300364

Objectives: The accuracy of FRAX® as a screening tool to identify osteoporosis and how it compares with tools such as Osteoporosis Self-Assessment Tool for Asians (OSTA), in Southeast Asian women has so far been unexplored. We aimed to determine the FRAX® thresholds that accurately identify densitometric osteoporosis and to compare its performance with that of OSTA for this purpose. Methods: Singaporean postmenopausal women (n = 1056) were evaluated. FRAX® Major Osteoporotic Fracture Probability (MOFP), Hip Fracture Probability (HFP) scores, and OSTA indices were calculated. Receiver operating characteristic (ROC) curves were constructed and via the Youden index, the optimal cut-off points of balanced sensitivity and specificity for dual energy X-ray absorptiometry (DXA)-defined osteoporosis were identified and the performance characteristics were compared. Results: A FRAX® MOFP threshold of ≥3.7% had sensitivity, specificity, positive predictive value and negative predictive value of 0.78 (0.73–0.83), 0.63 (0.59–0.66), 0.4 (0.36–0.44), and 0.9 (0.87–0.92), respectively in identifying osteoporosis. The corresponding values for a HFP threshold of ≥0.6% were 0.85 (0.80–0.89), 0.58 (0.55–0.62), 0.39 (0.35–0.43), and 0.92 (0.9–0.94) and that for an OSTA index cut-off of ≤ −1.2 were 0.76 (0.70–0.81), 0.74 (0.71–0.77), 0.48 (0.43–0.54), and 0.91 (0.88–0.93). The area under the ROC curves were 82.8% (79.9%–85.6%), 77.6% (74.2%–81%), and 79.6% (76.5%–82.8%) for OSTA, MOFP, and HFP thresholds respectively. Conclusions: FRAX® and OSTA perform comparably in identifying osteoporosis in our population. OSTA has only 2 parameters and may be simpler to use. However, FRAX® may also have a role in primary screening to identify the postmenopausal woman to be referred for DXA scanning and may help facilitate fracture risk reduction discussions with the patient.