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. (Clin. Lab. 2012;58:747-753. DOI: 10.7754/Clin.Lab.2011.110816)