THE IMPORTANCE OF DIETARY CALCIUM AND PHOSPHORUS IN THE SECONDARY HYPERPARATHYROIDISM OF PATIENTS WITH EARLY RENAL-FAILURE

Secondary hyperparathyroidism (HPT) was evaluated in 157 patients with chronic renal failure (CRF), It was noted that HPT developed early in CRF at a time when plasma calcium and phosphorous were within normal limits. As creatinine clearance decreased below 80 mL/m, there was a s ignificant decrease in plasma calcitriol and a slow and progressive si gnificant increment in plasma parathyroid hormone (PTH). The effect of dietary intake of calcium and phosphorous was evaluated in these pati ents with early renal failure (ERF), They were divided into two groups , Group A was placed on a protein- and phosphorous-restricted diet (10 days) followed by a daily phosphorous-load diet (10 days), Group B ha d similar sequential diets plus a calcium supplement throughout the st udy. Dietary protein and phosphorous restriction resulted in an amelio ration of the HPT only in the group of patients receiving calcium supp lementation. The phosphate-load diet resulted in worsening of HPT in b oth groups. In summary, a deficit of calcitriol occurs early in CRF, w hich in turn leads to a significant increase in PTH, Phosphorous restr iction, together with calcium supplementation, ameliorated the HPT of patients with ERF. (C) 1997 by the National Kidney Foundation, Inc.