Clinical manifestations of trace metal abnormality in hemodialysis patients: A multicenter collaborative study

A multicenter collaborative study was undertaken involving the prevalence of abnormal blood levels of 6 trace metals (copper, zinc, aluminum, lead, cadmium, and mercury) in hemodialysis patients to observe their clinical manifestations. The study involved 6 medical centers and 405 patients with end-stage renal disease who had been on maintenance hemodialysis for at least 4 months. Venous blood samples were collected from patients before initiating hemodialysis. Atomic absorption spectrophotometry was used to measure plasma levels of copper, zinc, and aluminum, as well as whole blood levels of lead, cadmium, and mercury. Additionally, clinical symptoms and other parameters related to intoxication or deficiency of these trace elements were simultaneously assessed. Those results indicated a high proportion of abnormally low plasma zinc levels (19%) and abnormally high aluminum levels (21%) in the 405 hemodialysis patients. A small portion of patients had symptoms attributed only to abnormally high blood levels of copper (7%) or cadmium (7%). The patients did not have any lead or mercury intoxication. Plasma zinc levels decreased with age but increased with dialysis duration. Plasma copper concentration increased with age but had no correlation with dialysis duration. Female patients had higher levels of plasma copper, blood lead, and blood mercury than did males. Moreover, no significant influence of different dialyzers on plasma or blood levels of these trace metals was found. On the basis of the above results, we can conclude that the abnormal metabolism of trace metals contributes to a part of the uremic symptoms unresolved by maintenance hemodialysis. Furthermore, environmental factors, diets, and the aging process with its accompanying altered gastrointestinal absorption-rather than the hemodialysis procedure- are most likely, responsible for the trace metal burden found in uremia.