Longitudinal study of serum zinc and copper levels in hemodialysis patients and their relation to biochemical markers.

A 6-mo longitudinal study of 48 hemodialysis patients (HPs) with chronic renal failure was performed. Three blood samplings were done. Samples of whole blood from each patient were collected during hemodialysis sessions after passing through the artificial kidney. Zinc and copper levels were measured by atomic absorption spectrometry. Additionally, 36 biochemical indexes were evaluated during the study. Fifty-two healthy matched controls were also considered. Mean serum zinc and copper concentrations in HPs were significantly decreased (Zn) and increased (Cu), when compared with healthy controls (p < 0.01). Zinc concentrations found in the first and second blood samplings from patients were significantly lower than those measured for the third sampling (p < 0.01). The etiology of chronic renal failure influenced the statistically serum Zn levels of patients (p < 0.05). Serum copper levels of HPs were significantly diminished by the existence of secondary associated diseases (p < 0.01). Uric acid and parathyroid hormone, and total-cholesterol and glutamic-pyruvic-transaminase levels were significantly (p < 0.05) and linearly related with serum zinc and copper concentrations, respectively. From all of indexes, creatinine, direct bilirubin, magnesium, calcium, parathyroid hormone, transferrin, and albumin were statistically modified along the longitudinal study (p < 0.05). Transferrin serum levels were significantly diminished in the third blood sampling, indicating the tendency toward anemia in the patients. This result is reinforced by low levels of biochemical and hematological indexes related with iron body staus.