The influence of a high calcium carbonate intake on bone disease in patients undergoing hemodialysis

Bone disease is one of the most common features of protracted uremia. It is due to a host of metabolic derangements, including an acquired defect in vitamin D metabolism, hypersecretion of parathyroid hormone, abnormalities in the renal handling of phosphate and chronic acidosis. The influence of maintenance hemodialysis on uremic osteodystrophy is still a matter of controversy regarding the rate of progression and the severity of skeletal disease, and the distribution of calcium and phosphate in the body following long-term treatment. This is especially true of the therapeutic policy of increasing the serum calcium concentration and thus inhibiting the secretion of parathyroid hormone.This study was undertaken to compare bone disease in two groups of patients, one treated with a dialysate calcium fixed at 6mg/100ml (which corresponds to the normal value for ultrafilterable calcium), and a second group that was treated additionally with a large daily intake of calcium carbonate in an attempt to increase the intestinal absorption of this ion. The results indicate that a) the latter regimen was capable of significantly reducing the rate of bone resorption and recalcifying osteomalacic lesions, and b) since serum calcium concentrations did not significantly differ in the two groups, the patients treated by dialysis alone presumably maintained their serum calcium concentration at the expense of their skeleton calcium stores