A list of device-specific thresholds for the clinical interpretation of peripheral x-ray absorptiometry examinations

Abstract

The UK National Osteoporosis Society (NOS) has recently issued new guidelines on the use of peripheral x-ray absorptiometry (pDXA) devices in managing osteoporosis. The NOS guidelines recommend a triage approach in which patients' bone mineral density (BMD) measurements are interpreted using upper and lower thresholds specific to each type of pDXA device. The thresholds are defined so that patients with osteoporosis at the hip or spine are identified with 90% sensitivity and 90% specificity. Patients with a pDXA result below the lower threshold are likely to have osteoporosis at the hip or spine, patients with a result above the upper threshold are unlikely to have osteoporosis, while those between the two thresholds require a hip and spine BMD examination for a definitive diagnosis. This report presents data from a multicenter study to establish the triage thresholds for a range of pDXA devices in use in the UK. The subjects were white female patients aged 55-70 years who met the normal referral criteria for a BMD examination. For each device, at least 70 women with osteoporosis at the hip or spine and 70 women without osteoporosis were enrolled. All women had hip and spine BMD measurements using axial DXA systems that were interpreted using the National Health and Nutrition Examination Survey (NHANES) reference range for the hip and the manufacturers' reference ranges for the spine. Data are presented for five different devices: the Osteometer DTX-200 (forearm BMD), the Schick AccuDEXA (hand BMD), the GE Lunar PIXI (heel BMD), the Alara MetriScan (hand BMD), and the Demetech Calscan (heel BMD). The clinical measurements were supplemented by theoretical modeling to estimate the age dependence of the triage thresholds and the effect of the correlation coefficient between pDXA and axial BMD on the percentage of women referred for an axial BMD examination. In summary, this study provides thresholds for implementing the new NOS guidelines for managing osteoporosis using pDXA devices. The figures reported apply to postmenopausal white women aged 55-70 years who meet the conventional criteria for a BMD examination. The results confirm that the thresholds are specific to each type of pDXA device and that the NOS triage algorithm requires 40% of women to have an axial DXA examination.

The relation between bone mineral density in the heel and pixel intensity in the mandibular jaw bone among elderly women

“…3 When using the portable Calscan device for OP screening, an upper and a lower triage threshold is applied, which classifies the study population into a group that in all probability has OP, a group that is unlikely to have OP and a group about which there is uncertainty and requires further analysis. 4 This procedure, in which the screened population is divided into three groups, allows an individual with OP in the hip or spine to be identified with 90% sensitivity and 90% specificity. 4 Because OP is such a widespread problem, there is an ongoing discussion of the benefit of a preventative screening.…”

“…4 This procedure, in which the screened population is divided into three groups, allows an individual with OP in the hip or spine to be identified with 90% sensitivity and 90% specificity. 4 Because OP is such a widespread problem, there is an ongoing discussion of the benefit of a preventative screening. OP affects all of the bones in the human body, including the mandible.…”

The Osteoporotic Effect of Arteriovenous Fistula on the Ipsilateral Upper Extremity in Hemodialysis Patients

“…In the absence of axial DXA, current guidelines recommend using peripheral measurements from the hand, forearm or heel to aid in treatment decisions in those with clearly identified clinical risk factors and can be used safely in population screening for osteoporosis (23,24). The UK National Osteoporosis Society suggested that peripheral devices (such as the phalangeal RA device that we used) Bakan be adopted in a triage role (23)(24)(25). A variety of devices are available for assessing sites in the peripheral skeleton, such as the hand, forearm or heel (25).…”

“…The UK National Osteoporosis Society suggested that peripheral devices (such as the phalangeal RA device that we used) Bakan be adopted in a triage role (23)(24)(25). A variety of devices are available for assessing sites in the peripheral skeleton, such as the hand, forearm or heel (25). The phalangeal RA device that we used measured phalangeal BMD from the second phalanges of the middle three digits, which made it suitable for use in this study and other studies of screening for osteoporosis (23,24).…”

“…The phalangeal RA device that we used measured phalangeal BMD from the second phalanges of the middle three digits, which made it suitable for use in this study and other studies of screening for osteoporosis (23,24). Blake, et al (25) recommended the hand as the preferred site for bone densitometry measurements. Low BMD is associated strongly and consistently with increased risk of fracture in otherwise healthy men and women (4,26,27).…”