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

• Chandran M
• Chin YA
• Choo KS
• Ang WC
• Huang XF
• Liu XM
• Tay D
• Aung TKK
• Ali A
• Thu WPP
• Logan S
• Yan SX
• Lekamwasam S
• Hao Y

• KMID: 2503943
• DOI: http://doi.org/10.1016/j.afos.2020.04.001

Abstract

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 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.
Results
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.
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.

Keyword

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