Effects of high CaCO3 supplements on serum calcium and phosphorus in patients on regular hemodialysis treatment.

The effect of high doses of CaCO3 on serum phosphorus and calcium (sPi,sCa) and the changes in serum aluminum (sAl) induced by Al(OH)3 interruption were investigated in patients on regular hemodialysis treatment. Some patients were administered Al(OH)3 and CaCO3, others only the former or the latter and others nothing. Al(OH)3 was stopped in all but one in whom it was only reduced, and CaCO3 was started or increased in all patients. A better control of sPi and serum Ca-Pi product was observed during high Ca supplementation, despite Al(OH)3 discontinuation, and was associated with a significant decrease of sAl. As expected, taking into account the dialysate Ca level of 4 mEq/l, a significant hypercalcemia occurred in some patients, especially in those who had a normal predialytic sPi without Al(OH)3 supplementation. Therefore, lowering the dialysate Ca concentration according to individual need and increasing interdialytic oral Ca supplements can be recommended with the dual purpose of keeping a positive Ca balance and correcting hyperphosphatemia.