Short- and long-term uses of calcium acetate do not change hair and serum zinc concentrations in hemodialysis patients

Calcium acetate (CaAc) acutely decreases absorption of concomitantly administered zinc gluconate (Hwang et al., AJKD 1992), but its long-term effect on zinc metabolism has not been studied. This study is intended to elucidate whether use of CaAc as phosphate binder on a daily basis affects zinc status in hemodialysis (HD) patients. Effects of CaAc on serum zinc were studied in 44 HD patients for 8 weeks (short-term). In 10 of these patients, the changes of serum and hair zinc were followed for 8 months (long-term). The daily dose of CaAc contained 25.35 mmol elemental calcium. Serum and hair zinc concentrations were measured by atomic absorptiometry. Our results were as follows. (i) in the short-term study, serum zinc concentrations did not show a significant difference compared to the baseline; (ii) in the long-term study, serum zinc concentrations showed no significant difference between different time points (11.0+/-0.5 in the beginning, 11.9+/-0.4 after 2 months, 11.4+/-0.4 after 4 months and 11.3+/-0.5 mu mol/L after 8 months, n=10). However, these values were all significantly lower than in the normal controls (15.7+/-0.5 mu mol/L, n=16); (iii) hair zinc content was not significantly different from the baseline level (2.7+/-0.1 in the beginning, 2.4+/-0.1 after 2 months, 2.6+/-0.2 after 4 months, 3.1+/-0.1 mu mol/g hair, and from that of normal controls, 2.7+/-0.2 mu mol/g hair). In conclusion, daily application of CaAc does not significantly interfere with zinc absorption and storage in HD patients. However, the comparable hair zinc content in the presence of decreased serum zinc concentrations indicates that the metabolic processing of zinc in HD patients is different from that of normal individuals.