Quantitative computed tomography for spinal bone mineral measurements in chronic renal failure.

ABSTRACT

The aim of this study was to assess non-invasively the status of spinal trabecular bone in patients with chronic renal failure and the influence of the disease stage. Single energy quantitative computed tomography (CT) was used in 89 patients with chronic renal failure to measure spinal trabecular bone equivalent density. 23 patients were independent of dialysis and 66 were receiving long-term haemodialysis. Spinal trabecular bone density of the patients was compared with locally determined normal ranges. Although trabecular bone mineral density (BMD) was lower (9% on average) in the patients who were not dependent on dialysis compared with the predicted mean normal values (BMDp) for age- and sex-matched normal subjects, the difference was not statistically significant. A statistically significant reduction was found in patients on dialysis (BMD/BMDp 0.75 +/- 0.16, Z-score -1.3). Osteosclerosis was found in 11 patients and they were excluded from the study. Longitudinal measurements in 42 patients on dialysis without osteosclerosis showed a 2.9% mean reduction in BMD/BMDp over a period of 8 months. All but one of the 16 haemodialysis patients with osteopenic spinal fractures had trabecular BMD values lower than the fracture threshold determined by our technique. In conclusion, end-stage chronic renal failure was associated with reduction in the spinal trabecular bone density.