The effect of replacing aluminium hydroxide with calcium acetate/magnesium carbonate on serum phosphorus control in haemodialysis patients.

Abstract

Calcium acetate/magnesium carbonate (MgCO3) is a phosphorus binder with advantages in terms of cost, safety and tolerance and it has a similar efficacy to other drugs. The objective of the study is to assess the effects of replacing aluminium hydroxide [Al(OH3)] with MgCO3 on phosphorus and calcium metabolism in a cohort of haemodialysis patients. We included 21 patients with phosphorus <5mg/dl, with Al(OH3) as the only binder. The conversion to MgCO3 was carried out without changing the number of pills. We recorded clinical-demographic characteristics, treatment for secondary hyperparathyroidism and laboratory parameters before conversion and every month for four months. Phosphataemia decreased from 4.52 ± 0.99 to 4.02 ± 1.07 mg/dl (p=.027), and there was a decrease in the calcium-phosphorus product from 40.20 ± 10.44 to 35.16 ± 11.06 mg2/dl2 (p=.037). We did not observe significant changes in levels of calcium, parathyroid hormone or 25-OH-vitamin D3. The daily number of pills prescribed was reduced from 3.33 ± 2.29 to 2.15 ± 2.21 (p=.020). Concomitant treatments were not altered. We observed an initial significant increase in magnesaemia from 2.21 ± 0.24 to 2.43 ± 0.39 mg/dl (p=.001), which subsequently remained stable. We found a decrease in serum aluminium from 14.91 ± 8.55 to 8.47 ± 3.98 µg/l (p=.004), with levels within the recommended range in all patients. MgCO3 allowed good control of serum phosphorus in haemodialysis patients who were previously well controlled with Al(OH)3, using fewer daily pills. There was a slight increase in serum magnesium, without short-term clinical significance. We do not know the effects of this increase in the longer term.