Bone Metabolism and Peritoneal Membrane Transport in Children on Chronic Peritoneal Dialysis

Abstract

The aim of the study was to assess the influence of peritoneal membrane permeability on bone metabolism in dialyzed children. 24 children with end-stage renal failure and being treated with peritoneal dialysis (PD) were studied. The children were divided into two groups based on the results of a standard peritoneal equilibration test: group I, high peritoneal transport [ratio of dialysate glucose concentration at 4 hours to dialysate glucose concentration at 0 hours (D/D0) < 0.26, dialysate-to-serum ratio of creatinine concentration at 4 hours (D/P) > 0.81], 10 children aged 9.9 +/- 2.9 years; group II, other peritoneal transport types (D/D0 > 0.26, D/P < 0.81), 14 children aged 11.4 +/- 2.7 years. Serum levels of calcium (sCa), phosphorus (sP), protein, albumin, alkaline phosphatase (AP), and parathormone (PTH) were measured, and bone biopsies were performed in all children. Alfacalcidol and calcium carbonate doses were adjusted to sCa, sP, and PTH levels in all patients. No statistically significant differences (NS) between the two groups were found in age, duration of PD, sCa, sP, AP, PTH, protein, or albumin levels. The mean alfacalcidol dose was 0.055 +/- 0.057 microg/kg body weight/ week in group I and 0.099 +/- 0.065 microg/kg/week in group II (p = NS). In group I, the high peritoneal transport group, significantly lower osteoclast surface (OcS/BS) and bone formation rate (BFR/TV) were found compared with group 11 (3.1% +/- 1.7% vs 4.6% +/- 2.0%, and 483.5 +/- 329.2 microm3/mm2/day vs 913.9 +/- 558.3 microm3/mm2/day, respectively, p < 0.05). We also found significant positive correlation between D/D0 and BFR/TV and OcS/BS (r = 0.45, p < 0.05). Bone turnover in children treated with PD may depend on peritoneal permeability.