Ability of peripheral bone assessments to predict areal bone mineral density at hip in community-dwelling elderly men

Abstract

We present cross-sectional data on bone mineral density (BMD) and quantitative ultrasound (QUS) indices in an ambulatory elderly male population (n = 235). Dual X-ray absorptiometry (DXA) at the proximal femur was considered the reference assessment site and was compared with DXA at the forearm and heel and to QUS at the heel and midtibia. Correlations and weighted kappa analysis indicate an only moderate concordance of absolute values between peripheral bone assessment and total hip DXA (weighted kappas: 0.31-0.45). Discrepancies are even more important when T-scores and prevalence rates of osteoporosis are considered, owing to factors related to the reference populations used. Predictive value of peripheral measurements for osteoporosis diagnosed on the basis of hip BMD by DXA, as assessed by receiver operator characteristic analysis, was moderate and comparable for all peripheral measurements (area under the curve: 0.708-0.870), with the exception of a clearly lower predictive value for QUS at the tibia. Discrimination of male subjects with a history of at least one fragility fracture was significant for DXA at the proximal femur and QUS at the heel. It is concluded that peripheral measurements cannot be used as a substitute for hip DXA. However, they might be useful to guide patient referral for central DXA.