Long-term CaCO3 treatment of chronic hemodialysis patients: an attempt to prevent aluminum osteopathy.

Long-term CaCO3 treatment of chronic hemodialysis patients was studied. Single doses of CaCO3 were given to 25 patients, 23 of whom had been receiving Al(OH)3 before the study. When predialysis serum calcium (Ca) rose to greater than 5.5 mEq/L, CaCO3 was reduced and Al(OH)3 was administered again. Eighteen months later, serum phosphate (P) was well controlled, and predialysis serum P was less than 6.5 mg/dl in 14 patients given CaCO3 alone. Alkaline phosphatase (ALP) levels significantly decreased, and serum aluminum was remarkably lowered in patients who had discontinued Al(OH)3. In patients who resumed Al(OH)3, ALP levels rose after Al(OH)3 administration. Although levels of c-PTH did not change in CaCO3 treated patients, six patients with poor control of serum P before the study showed a significant decrease in c-PTH. These data indicate that CaCO3 is an effective P binder that stops the progression of silent osteopathy, presumably caused by oral intake of Al(OH)3, and may ameliorate these changes. However, further effort will be necessary to develop means to control serum Ca, because long-term use of CaCO3 induced hypercalcemia in half the patients.