Renal Osteodystrophy in Patients on Continuous Ambulatory Peritoneal Dialysis: A Five Year Study

The clinical, biochemical, radiological and histopathological data related to renal osteodystrophy were extracted from the computer records of 81 patients who had been treated by continuous ambulatory peritoneal dialysis (CAPD) for more than two years. Paired bone histopathology was available in 45 of these patients. The majority maintained normal serum ionised and total calcium concentrations, while mean serum phosphate concentration ranged from 1.68 to 1.80 mmol/l. Serum parathyroid hormone concentrations fell significantly in those with high values at the start of CAPD. Five patients underwent parathyroidectomy. Mean serum aluminium concentrations were higher than normal healthy controls and the levels rose further after the addition of aluminium-containing phosphate binders (ACPB). Of the patients with histological evidence of secondary hyperparathyroidism, 82% showed improvement on repeat biopsy. Nine, who had no evidence of osteitis fibrosa at the beginning of CAPD, remained free of bone disease during the study period. Osteomalacia was present in two patients at the onset of CAPD and developed in three more, two of them after parathyroidectomy. Except for one patient, all those with osteomalacia improved after the addition of alfacalcidol and continuation of CAPD. This last patient died with evidence of aluminium deposition in his bones. We conclude that when used as clinically indicated, CAPD, with the addition of calcium carbonate, phosphate binders and alfacalcidol, achieves good control of renal osteo dystrophy in the majority of patients.