Hyperphosphatemia and
hyperparathyroidism, frequently observed in patients with endstage renal disease, are associated with
renal osteodystrophy, organ calcification,
cardiovascular disease and
sudden death. Restriction of
dietary protein and
phosphorus is beneficial in slowing the progression of
renal failure.
Dietary phosphorus restriction must be prescribed at all stages of
renal failure in adults. It may be achieved by decreasing
protein intake and avoiding foods rich in
phosphorus. An average of 60-80% of the
phosphorus intake is absorbed in the gut in dialysis patients. If
phosphate binders are employed, the
phosphorus absorbed from the diet may be reduced to 40%. Conventional
hemodialysis with a high-flux, high-efficiency dialyzer removes approximately 30 mmol (900 mg)
phosphorus during each dialysis performed three times weekly. Therefore, 750 mg of
phosphorus intake should be the critical value above which a positive balance of
phosphorus may occur. This value corresponds to a
protein diet of 45-50 g/day or 0.8 g/kg
body weight/day for a 60 kg patient. Target levels should become 9.2-9.6 mg/dl for
calcium, 2.5-5.5 mg/dl for
phosphorus, <55 mg2/dl2 for the
calcium-
phosphorus product, and 100-200 pg/ml for intact
parathyroid hormone.