Total body calcium and long-term calcium balance in chronic renal disease.

Abstract

Abstract Renal bone disease is a common cause of morbidity in patients with end-stage renal failure undergoing dialysis. The natural history of this entity and the effect of dialysate calcium concentrations have been studied in 26 chronic dialysis patients by total body calcium (TBC) measurement with neutron activation analysis (NAA), bone biopsies, calcium absorption, hand radiographs, serum chemistry, and skin calcium determinations. Calcium balance was measured by serial NAA over intervals up to 27 months. Total body calcium (TBC) ranged from 503 to 1,392 Gm. and in the 24 males averaged 1,116 Gm. or 96 ± 12 per cent of predicted normal. Bone fractures occurred in 5 of 8 patients with TBC less than 90 per cent of predicted normal and in only 2 of 16 patients with TBC greater than 90 per cent of predicted normal. The relationship of TBC and calcium balance with bone biopsy suggested that osteomalacia and fibrosis may be different disease entities. Osteomalacia was characterized by low TBC (87 per cent of predicted normal) and progressively negative calcium balance (−5.0 per cent TBC per year). Fibrosis was characterized by normal to high TBC (106 per cent of predicted normal) and stable calcium balance (−0.2 per cent TBC per year). A change in dialysate calcium from 3.0 to 4.0 mEq. per liter appeared to have a beneficial effect on calcium balance. Eleven patients observed on a dialysate bath of 3.0 mEq. per liter calcium over 12.2 patient-years experienced a cumulative TBC loss of 34.1 per cent. On the other hand, 10 patients observed on a 4.0 mEq. per liter calcium dialysate over 10.3 patient-years experienced a cumulative gain in TBC of 2.3 per cent.