Essential trace element status and clinical outcomes in long-term dialysis patients: A two-year prospective observational cohort study

Background & aims: Essential trace elements are involved in many biological processes for normal cell function including immunological defense against oxidation and infection. Deficiency of these elements generally leads to illness or even death in the general population. Therefore, we investigated the predictive values of trace element status on clinical outcomes in dialysis patients, who are more prone to trace element deficiency. Methods: We enrolled 111 prevalent patients on maintenance dialysis from a Taipei tertiary-care referral hospital and measured serum levels of selenium, copper, and zinc. Patients were followed for 2 years or until death or withdrawal. Results: Multivariate Cox regression analysis indicated that patients with diabetes mellitus (HR, 2.162 [95% CI, 1.105-4.232], p= 0.024), prior stroke (HR, 3.876 [95% CI, 1.136-13.221], p= 0.030), and zinc deficiency (HR, 0.979 [95% CI, 0.966-0.992], p= 0.002) were more likely to be hospitalized for infectious diseases. Furthermore, beyond traditional risk factors, such as old age and hypoalbuminemia, multivariate Cox regression also indicated that lower serum level of zinc independently predicts overall mortality (HR, 0.973 [95% CI, 0.948-0.999], p= 0.046). Conclusions: In long-term dialysis patients, the serum level of zinc was an independent predictor of future hospitalization due to infectious diseases and of overall mortality.