The relationship of an Asian-specific screening tool for osteoporosis to vertebral deformity and osteoporosis

Abstract

An Asian-specific screening tool for osteoporosis, the so-called OSTA index, was devised and is likely to be helpful in determining which postmenopausal women need bone mineral density (BMD) measurement. Besides BMD, prevalent vertebral fracture is a strong risk factor for future fractures. However, the relationship of the OSTA index to prevalent vertebral fractures is currently unknown. In this study, we evaluated the performance of the OSTA index in elderly Thai women and assessed the relationship of the index to prevalent vertebral deformities. Subjects consisted of 741 healthy Thai elderly women. BMD was measured by DEXA and T-score <or=2.5 SD is defined as osteoporosis. Prevalent vertebral deformities were determined by morphometric X-ray absorptiometry. OSTA index >-1 is classified as having low risk of osteoporosis, -1 to -4 as intermediate risk and, <-4 as high risk. Data were expressed as mean +/- SD. The mean age and body weight of subjects were 67 +/- 4.8 years and 57.8 +/- 8.7 kg, respectively. The area under the ROC curve for OSTA index to identify osteoporosis at femoral neck and lumbar spine was 0.80 and 0.72, respectively. Femoral neck osteoporosis was found in 40.4%, 6.3%, and 2.4% of subjects with high-risk, intermediate-risk, and low-risk OSTA indexes, respectively. With regard to vertebral deformities, the area under the ROC curve relating OSTA index to vertebral deformities was 0.70 (P < 0.001). The prevalence of vertebral deformities in according to the OSTA index was 19.2% in the high-risk, 7.9% in the intermediate-risk, and 2.8% in the low-risk group. We concluded that the OSTA index can be of assistance in the selection of postmenopausal women for BMD measurement. In addition, this index may be helpful in the identification of postmenopausal women with vertebral deformity and those who need antifracture treatments.