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

ABSTRACT

INTRODUCTION: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.