Concentrations of Trace Elements and Clinical Outcomes in Hemodialysis Patients: A Prospective Cohort Study

Background and objectives Deficiency of essential trace elements and excess of potentially toxic trace elements are common in patients on hemodialysis. Whether these abnormalities are associated with poor outcomes is unknown but worth investigating, because they are potentially treatable. Design, setting, participants, & measurements We did a prospective longitudinal study of 1278 patients on incident hemodialysis, assessing blood concentrations of 25 trace elements at baseline. We used adjusted logistic regression to evaluate the association between trace element status and four outcomes (death, cardiovascular events, systemic infection, and hospitalization). A priori hypotheses concerned ( 1 ) deficiency of zinc, selenium, and manganese and ( 2 ) excess of lead, arsenic, and mercury. Concentrations of the other 19 elements were tested in hypothesis-generating analyses. Results Over 2 years of follow-up, 260 (20%) patients died, 285 (24%) experienced a cardiovascular event, 117 (10%) were hospitalized for systemic infection, and 928 (77%) were hospitalized for any cause. Lower concentrations of zinc or manganese and higher concentrations of lead, arsenic, or mercury were not independently associated with higher risk of clinical outcomes. Lower concentrations of selenium were strongly and independently associated with death (odds ratio, 0.86 per decile; 99.2% confidence interval, 0.80 to 0.93) and all-cause hospitalization (odds ratio, 0.92 per decile; 99.2% confidence interval, 0.86 to 0.98). In exploratory analyses, higher copper concentrations were significantly associated with higher risk of death (odds ratio, 1.07 per decile; 99.2% confidence interval, 1.00 to 1.15), and cadmium levels in the highest decile were associated with higher risk of death (odds ratio, 1.89; 99.2% confidence interval, 1.06 to 3.38). Conclusions Lower levels of zinc or manganese and higher concentrations of lead, arsenic, or mercury were not associated with higher risk of clinical outcomes, but lower concentrations of selenium were strongly and independently associated with the risks of death and hospitalization.