Overestimation of osteopenia using standard analysis software for peripheral quantitative computed tomography.

It is well established that measurement of bone mineral density (BMD) can estimate the risk of future fractures. To assess individual fracture risk BMD measurements are compared with a reference range provided by the manufacturer of the respective BMD technology. However, the power of trabecular bone measured by peripheral quantitative computed tomography (pQCT) to predict future fractures has not been shown up to now. We conducted measurements of trabecular bone density (TBD) at the distal radius (pQCT XCT 900, Stratec, Germany) in a sample of 506 healthy white women aged 40-60 years (mean 48) and compared the results with the manufacturer's normal range. We found a remarkable difference in TBD values between our healthy study population and the manufacturer's reference data in all age groups (e.g., age 50-54 years, 143.1 +/- 43.2 mg/cm3 versus 181.1 +/- 39.0 mg/cm3). Compared to the +/- 2 SD limits of the manufacturer's reference range our study population showed mean TBD values that were about 1 SD below the mean of the reference range. About 50% of our healthy cohort were below the -1 SD limit of the reference range. Almost ten times as many normal subjects as expected (22.1%) were found below the -2 SD limit and therefore classified as individuals with increased fracture risk. This overestimation of fracture risk leads to discomfort of the patient, unnecessary therapeutic intervention, and significant costs to the public.(ABSTRACT TRUNCATED AT 250 WORDS)