Correlation of bone alkaline phosphatase and iPTH with some basic biochemical markers in predialysis and dialysis patients.

BACKGROUND: Bone alkaline phosphatase (BALP) is a direct and independent indicator of impaired bone turnover. We intended to find out whether there are any significant changes in BALP and iPTH levels, in comparison to total Ca, total Mg, inorganic P, total alkaline phosphatase (ALP), and tartrate resistant acid phosphatase (TRAP) in predialysis and dialysis patients. METHODS: Out of 266 patients investigated, 114 were on continuous ambulatory peritoneal dialysis, 112 were on maintenance haemodialysis, while 40 predialysis patients had end stage renal disease. The parameters were analysed according to the manufacturers' instructions. RESULTS: Correlations were established for the bone marker concentrations analysed among the studied groups. The largest ranges were determined for BALP and iPTH. Predialysis and dialysis patients showed very low levels of BALP. Dialysis patients had lower levels of iPTH (p < 0.001), while in predialysis patients the levels were significantly higher (p < 0.05) than recommended for low bone turnover, according to K/DOQI. CONCLUSIONS: The observations made in this study identify BALP as a good indicator of decreased bone turnover in predialysis and dialysis patients. However, in order to reveal a difference between bone activity and the level of parathyroid activity and its effect on bone turnover, it is always necessary to observe both BALP and iPTH levels.

Relation between 25(OH)-vitamin D deficiency and markers of bone formation and resorption in haemodialysis patients.

Deficient serum 25-hydroxyvitamin D [25(OH)D] may contribute to the impaired bone turnover of end stage renal disease patients. In 112 hemodialysed patients we analysed the relation between 25(OH)D and bone alkaline phosphatase (BALP), beta-CrossLaps (beta-CTx) and iPTH. We analysed parameters according to the manufacturers' instructions. We found potentially significant vitamin D deficiency: 71% of patients had 25(OH)D levels below 50 nmol/L. In patients with iPTH below 150 pg/mL (n = 57), we observed significantly low 25(OH) (p < 0.01). In addition, patients with iPTH above 300 pg/mL had higher BALP levels (p < 0.05). There were negative correlations between serum 25(OH)D and both BALP and iPTH (r = -0.225, p < 0.05 and r = -0.331, p < 0.05). Beta-CTx levels were significantly higher in patients who did not receive vitamin D supplementation (p < 0.01). In addition, reduced BALP and iPTH levels indicate decreased bone turnover. Recorded data could signify that vitamin D deficiency may contribute to the impaired bone metabolism of hemodialysis patients.