Trace elements in hemodialysis patients: a systematic review and meta-analysis.
BACKGROUND
Hemodialysis patients are at risk for deficiency of essential trace elements and excess of toxic trace elements, both of which can affect health. We conducted a systematic review to summarize existing literature on trace element status in hemodialysis patients.


METHODS
All studies which reported relevant data for chronic hemodialysis patients and a healthy control population were eligible, regardless of language or publication status. We included studies which measured at least one of the following elements in whole blood, serum, or plasma: antimony, arsenic, boron, cadmium, chromium, cobalt, copper, fluorine, iodine, lead, manganese, mercury, molybdenum, nickel, selenium, tellurium, thallium, vanadium, and zinc. We calculated differences between hemodialysis patients and controls using the differences in mean trace element level, divided by the pooled standard deviation.


RESULTS
We identified 128 eligible studies. Available data suggested that levels of cadmium, chromium, copper, lead, and vanadium were higher and that levels of selenium, zinc and manganese were lower in hemodialysis patients, compared with controls. Pooled standard mean differences exceeded 0.8 standard deviation units (a large difference) higher than controls for cadmium, chromium, vanadium, and lower than controls for selenium, zinc, and manganese. No studies reported data on antimony, iodine, tellurium, and thallium concentrations.


CONCLUSIONS
Average blood levels of biologically important trace elements were substantially different in hemodialysis patients, compared with healthy controls. Since both deficiency and excess of trace elements are potentially harmful yet amenable to therapy, the hypothesis that trace element status influences the risk of adverse clinical outcomes is worthy of investigation.
Tonelli
Marcello
M
Department of Medicine, University of Alberta, Edmonton, Alberta, Canada. mtonelli-admin@med.ualberta.ca
Wiebe
Natasha
N
Hemmelgarn
Brenda
B
Klarenbach
Scott
S
Field
Catherine
C
Manns
Braden
B
Thadhani
Ravi
R
Gill
John
J
D001774:Blood Chemical Analysis; D006801:Humans; D010949:Plasma / Q000737:chemistry*; D006435:Renal Dialysis / Q000009:adverse effects*; D044967:Serum / Q000737:chemistry*; D014131:Trace Elements / Q000032:analysis* / Q000494:pharmacology*
D014131:Trace Elements