[Altered calcium-phosphorus metabolism and low-protein diet]

Many metabolic disorders associated with uremia can affect the long-term survival of patients with chronic kidney disease. Such disorders can be defined as: hypocalcemia, increased levels of phosphorus, reduced synthesis of 1,25-dihydroxyvitamin D and serum calcitriol, and reduced expression of vitamin D receptors on parathyroid cells with increased parathyroid hormone levels and secondary hyperparathyroidism. Phosphorus, which plays a crucial role in the progression of progressive renal disease, has been shown to be an independent risk factor for death in hemodialysis patients. Thus, reducing the phosphorus intake by decreasing dietary proteins may slow the progression of renal disease. Hypocalcemia is typically associated with chronic kidney disease. It is due to the reduced intestinal absorption of calcium and the spontaneously reduced protein intake that occur in patients with progressive renal disorders. Activated vitamin D and calcium supplements should be administered to patients who are following low-protein diets to prevent secondary hyperparathyroidism; the doses should be correlated with actual renal function and protein intake.