Osteoporos Sarcopenia.  2020 Jun;6(2):53-58. 10.1016/j.afos.2020.04.001.

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

  • 1Osteoporosis and Bone Metabolism Unit, Department of Endocrinology, Singapore General Hospital, Singapore
  • 2Department of Endocrinology, Singapore General Hospital, Singapore
  • 3Department of Dermatology, Changi Genera Hospital, Singapore
  • 4Division of Medicine, Sengkang General Hospital, Singapore
  • 5Department of Obstetrics and Gynaecology, National University Hospital, Singapore
  • 6Department of Nuclear Medicine and Molecular Imaging, Singapore General Hospital, Singapore
  • 7Faculty of Medicine, University of Ruhuna, Galle, Sri Lanka
  • 8Health Services Research Unit (HSRU), Singapore General Hospital, Singapore


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.
Singaporean postmenopausal women (n ¼ 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.
A FRAX® MOFP threshold of 3.7% had sensitivity, specificity, positive predictive value and negative predictive value of 0.78 (0.73e0.83), 0.63 (0.59e0.66), 0.4 (0.36e0.44), and 0.9 (0.87e0.92), respectively in identifying osteoporosis. The corresponding values for a HFP threshold of 0.6% were 0.85 (0.80e0.89), 0.58 (0.55e0.62), 0.39 (0.35e0.43), and 0.92 (0.9e0.94) and that for an OSTA index cut-off of  1.2 were 0.76 (0.70e0.81), 0.74 (0.71e0.77), 0.48 (0.43e0.54), and 0.91 (0.88e0.93). The area under the ROC curves were 82.8% (79.9%e85.6%), 77.6% (74.2%e81%), and 79.6% (76.5%e82.8%) for OSTA, MOFP, and HFP thresholds respectively.
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.


Asia; Assessment threshold; FRAX; OSTA; Osteoporosis; Screening
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