Bone Mineral Density in Haemodialysis Patients: A Comparative Study of Dual-Energy X-Ray Absorptiometry and Quantitative Ultrasound

Abstract

Background. Quantitative ultrasound (QUS) of bone is a relatively new technique that appears to assess 'bone quality' in addition to bone mineral density. The purpose of this study was to evaluate the diagnostic potential of QUS of calcaneum and to correlate it with dual energy X-ray absorptiometry (DEXA) in chronic haemodialysis patients. Methods. Broad-band ultrasound attenuation (BUA; dB/MHz) and speed of sound (SOS; m/s) of calcaneum and DEXA (g/cm(2)) measurements of the lumbar spine and hip were made in 39 patients. The indices obtained by either method were compared with age-and sex-matched controls. Calcaneal measurements were correlated to DEXA and relevant clinical and biochemical data of patients. Results. BUA and SOS values were markedly reduced in dialysis patients compared to controls (59.1+/-13.8 vs 73.0+/-16.2 dB/MHz, P<0.001 and 1533+/-28 vs 1560+/-29 m/s, P=0.014 respectively). There was a moderate, but significant association between calcaneal parameters and DEXA (r = 0.32-0.53, P < 0.05). Both BUA and SOS scores were inversely correlated with age (r = -0.69, P < 0.001) and duration of menopause (r = -0.74, P < 0.01). Additionally, BUA values showed a moderate negative association with serum intact parathyroid values (r = -0.38, P = 0.018). Conclusion. Chronic haemodialysis patients have reduced calcaneal BUA and SOS scores. QUS of the calcaneum is an easy-to-apply and radiation-free technique. It could be a useful substitute for assessment of bone density in such patients. However, further studies in large patient groups and comparisons with plasma markers of bone turnover and bone biopsy findings are needed to assess its potential place in the management of renal osteodystrophy.