| Abstract
| - Background. The bone abnormalities that lead to symptomatic renal osteodystrophy commence early in the course of renal failure, but the optimal time to start treatment needs clarifying. The present study examined the effect of alfacalcidol treatment on bone metabolism and bone density in patients with pre-dialysis chronic renal failure (CRF) in a prospective, randomized, placebo-controlled double blind design. Methods. Repetitive measures of bone mineral density (BMD) estimated by dual energy X-ray absorptiometry and plasma levels of biochemical markers of bone turnover [osteocalcin, bone alkaline phosphatase, propeptide of type-I collagen (PICP) and telopeptide of type-I collagen] and parameters of calcium homeostasis were performed in 36 patients with a glomerular filtration rate (GFR) of 6-60 ml/min. Results. A significant difference in BMD between the treatment groups in favour of the alfacalcidol-treated patients was found in the spine (4.2%), the femoral neck (4.9%) and the total femur (3.0%) (P<0.05). In the alfacalcidol group, plasma levels of parathyroid hormone 1-84 decreased from baseline values by 47±9%, and p-osteocalcin and bone alkaline phosphatase decreased by 24±9% and 48±8%, respectively (P<0.05). In the placebo group, PICP increased by 32±26% (P<0.05). No significant changes were found in plasma levels of vitamin D metabolites. GFR decreased significantly from baseline values in the alfacalcidol group (by 28±4 ml/min) and in the placebo group (by 26±5 ml/min) (P<0.05), with no difference being detected between the groups. Conclusions. Long-term treatment with alfacalcidol is safe and might be beneficial for the preservation of bone mass in the pre-dialysis stages of CRF, most likely through a reduction in bone turnover as estimated from the changes of the biochemical bone markers.
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