[Renal osteodystrophy in dialysis patients as estimated by three-point bone densitometry]

The aim of a study was to estimate the renal osteodystrophy status using bone densitometry in relation to selected biochemical parameters of calcium-phosphate metabolism. The study population consisted of 123 patients with end-stage renal disease, including 24 patients treated with continuous ambulatory peritoneal dialysis (CAPD), aged between 22 and 73 years (mean 49.9 years), on dialysis program for mean period of 14.9 months and 99 patients on maintenance hemodialysis for mean period of 58.8 months, aged between 19 and 72 years (mean 46.6 years). Densitometric measurements using DEXA technique were performed in three different skeletal points: distal ends of both radial bones, lumbar spinal region and femoral neck. Concomitantly, serum concentrations of total and ionized calcium, phosphates and parathormone as well as alkaline phosphatase serum activity were measured. Among male patients treated with CAPD significantly higher BMD values in right forearm were found as compared to women treated with this method (0.769 vs. 0.616; p < 0.001). Higher values of BMD were also found in both forearms in whole CAPD population as compared to those on hemodialysis. However, there was no difference in densitometry results between CAPD and HD patients as well as between men and women within these groups, when measured in femoral neck and lumbar spinal region. Among hemodialysis patients higher levels of phosphates and PTH were found as compared to CAPD, doses of drugs used for treatment of osteodystrophy--calcium carbonate, aluminum hydroxide and active vitamin D were also higher in individuals on HD. In addition, in CAPD patients statistically significant, positive correlations were found between BMD value in lumbar spinal area as well as in femoral neck and amount of ingested calcium carbonate, between BMD in lumbar spinal area and aluminum hydroxide dose taken by patients and between BMD in both forearms and dose of active vitamin D. We failed to demonstrate any relationship between obtained densitometric results as well as biochemical markers of calcium-phosphate metabolism and quantitative parameters of dialysis adequacy in both treatment modes. Obtained results let us to conclude that renal osteodystrophy is less advanced in patients treated with peritoneal dialysis, however this may be related only to markedly shorter renal replacement therapy period in this group. Lack of significant abnormalities in densitometry measurements taken in lumbar spinal area and femoral neck, while they are present in forearms, may suggest that the latter point of skeleton may be most useful for identification of bone mass deficiency in dialyzed patients.