OST Risk Index and Calcaneus Bone Densitometry in Osteoporosis Diagnosis

Abstract 

The gold-standard method for osteoporosis diagnosis is by dual-energy X-ray absorptiometry (DXA) of the lumbar spine and/or hip. DXA is expensive and alternative approaches are being analyzed. The objective of this study was to evaluate whether the Osteoporosis Self-Assessment Tool (OST) combined with calcaneal DXA improves the sensitivity and specificity of the DXA. One hundred and sixty-one (67 males and 94 females) outpatients referred due to suspected osteoporosis or lumbar pain were included. Hip, spinal, or calcaneal DXA was performed in all patients and the OST index was administered. The cutoff point for patients of high- or low-risk osteoporosis was 2 for women and 3 for men. The mean OST index value was 3.62±4.3. Twenty-seven percent of the patients were osteoporotic. Sixty-two percent presented a low risk and 38% a high risk. In men, the OST had a sensitivity of 39% and a specificity of 86%, whereas in women the sensitivity was 94% with a specificity of 59%. The combination of the calcaneal DXA with the OST index did not modify the validity of DXA in men. In women, the sensitivity of the different cutoff points was improved at the expense of a decrease in the specificity without modifying the area under the curve. The combination of the calcaneal DXA with the OST index did not improve the value of each of the separate techniques. The OST index is useful in women to facilitate the densitometry indication for hip and/or spine.

Key Words: Central densitometry, OST, osteoporosis, peripheral densitometry